Britax-Romer is the brand - I guess it's probably the Dualfix you've had? That is their seat that goes rear facing and forward facing (there is another but it's newer so probably not what you have).
Axkid are good seats, and if your DC is happy rear facing then it's beneficial to carry on as it does offer the best safety.
Equally though I also think it's totally reasonable to forward face at 3.5 if that's your decision. It is never safer to forward face, except for the driver! But even in Sweden the majority of parents move to forward facing between the ages of 3y3m and 3y9m according to an observational study by Besafe.
The reason that you'll get conflicting opinions/advice is that basically we are talking about risk and probability not absolutes. Even with a rear facing car seat, there will unfortunately be some accidents that are so severe the passengers of the car do not survive. And forward facing car seats do offer better protection than seatbelt alone or being unrestrained.
So there are minor accidents where it doesn't matter if your DC is in a forward or rear facing seat, it will protect them. There are severe accidents where it doesn't matter if your DC is in a forward or rear facing seat because no seat could protect them. Then there are accidents in the middle where if a child is in a FF seat they might not survive whereas if they had been RF they would. This is the gap in protection between RF and FF.
As children get older, the gap reduces. For example at one year old, the gap is very large. So large that most countries in the world have a minimum allowable age to forward face. For example, American states have either 1 year or 2 years. The newer EU/UK regulation is 15 months. The gap is so large that it is actually illegal to use a forward facing seat for a younger child. But as children get older, the gap reduces so that the probability you'll be in an accident where it actually matters is much smaller.
So basically people's risk tolerance is just different and it will also depend on other factors.
If you are the kind of person who wants to know, in the event that you were in an accident, that you all have the very best possible protection and are covered for as many eventualities as possible, and/or you do a lot of driving and/or you do more driving on country roads (probability of serious accidents) or motorways (low chance of accident but high severity when they happen) then rear facing up to the limit of the largest capacity ERF seat OR if you have a child who is smaller for their age, rear facing until you are 100% happy to put them into a booster seat is a very good choice. This is typically the choice that ERF advocates see as the absolute only option. They would like to see forward facing, 5 point harness seats completely phased out and a minimum age of more like 4-5 to change to a high backed booster seat.
But there are other viewpoints - personally I am of the view that this kind of rhetoric is unhelpful because the same solution will not fit everybody. If you are happy with ERF and you can afford it and it is comfortable and your child is happy with it and it fits your car etc then - absolutely all fine, and I'm really happy these seat options exist and def support people raising awareness of them.
And I think there are a lot of ERF myths out there so if you are worried you can't afford an ERF seat, I will help you find a cheaper one. If you are worried your car won't fit an ERF seat, I will help with graphics and videos and help you find a local stockist who can try different options in your car. If you need to fit 3x seats across the back of an ordinary car, ERF is actually pretty good for this. If you are worried about legs or travel sickness or children getting bored, I will happily share some resources and explanations about this. We have an inherent bias against ERF because it is not what we are used to/familiar with and it's human nature to gravitate towards what we are familiar with. So I totally 100% agree with the ERF enthusiasts that these are barriers we can break down and smash the myths.
Where I disagree with ERF enthusiasts is that I think there ARE scenarios where the safety benefits of ERF don't actually outweigh the other factors.
For example, some of the longer-lasting ERF seats ARE more expensive than forward facing seats, and this could cause financial difficulty for some. I don't think people should go into debt to get a better car seat. Buy the best you can comfortably afford.
When someone already owns a forward facing seat, it is not always worth it to replace with a rear facing one. That's the parent's own decision to be made.
When a child extremely dislikes rear facing, I do not think it is worth pushing through distress and discomfort for every single journey just for a theoretical benefit in a crash which might never happen. You have to weigh the everyday, small risks (discomfort, distress) with the possible-but-unlikely big risks (serious neck/head injury, death) - again it's up to the individual to weigh this up, and think about whether this is a behaviour issue and might go away if the parent insists (e.g. some children hate being strapped in, but we persist with this, distract, reward etc and most of the time they get over it), or whether it's a genuine discomfort issue that won't.
When it is impossible to use a rear facing seat safely (e.g. child frequently escapes but does not FF) you have to weigh up the ACTUAL risks, not the theoretical one - ie - while yes, RF is safer than FF, FF is MUCH safer than unrestrained.
And, lastly, there are ways to make FF safer. One of the huge benefits of ERF is that RF seats do a lot of compensation for improper use. If you have a loose harness, winter clothing, improper headrest position etc this simply does not matter as much with RF seats because the shell of the seat is doing so much of the restraint and you can't get the shell wrong except for, perhaps, totally wrong installation. The features of the seat itself also make much more of a difference when FF. It is very difficult to create a FF seat which does its job well. There are better and more basic FF seats, whereas even the most basic RF seat will do a good job at protection. The specific model of seat and how accurately it is used makes much more of a difference FF.
But where I have a problem with the ERF groups is that IRL, many many parents DO choose forward facing, they DO choose to use booster seats too young etc. To me, just saying "Only ERF is acceptable" is like an abstinence-only approach to sex education. There is a discussion to be had about what features are useful in FF seats and which are just marketing fluff. There is a useful discussion about what types of misuse happen and how to prevent them and so on. And to be fair the ERF groups tend to be pretty hot on misuse (but they also only then focus on RF seats, so people don't understand for example that in many seats, inserts should not be used when FF). If you can afford a £25 seat or a £100 seat, is there really a difference between them and what is that? I think these are really important conversations to have and those are missing in the ERF enthusiast space where the answer is always the latest ERF model.