I'm a FTM too and agree it's a minefield! I was lucky I got to visit a few shops and try a few out and ended up buying just a day or 2 before lockdown.
I second the advice to really think about how you will use it, what your personal needs are.....will you be in and out of a car a lot? will you be walking on different terrains? will you be using public transport regularly? do you live in a city or countryside? etc etc. It makes a difference.
For example, I don't have a car so will be mostly walking so decided against a full travel system. Instead I will buy a car seat separately for occasional use which can easily go in and out of different vehicles. Attaching it to the puschair frame isn't important to me and I doubt I will ever need to do that, but if I did, you can buy adapters to allow most car seats to attach to most pushchair chassis.
Because I walk a lot, I knew I wanted a carrycot and not just a lie flat pushchair. They're bulkier and heavier as the frame won't fold down as small but, as i'm not going to be in and out of cars or on public transport everyday, that was less important to me.
For me personally, It was more important that it was sturdy and substantial with good quality wheels suitable for walking on different terrains and, as I'm quite tall, adjustable handlebars/a higher chassis were a must too.
I went for a Joolz Day 3 in the end and I love it.
If you find one you like but are put off by the price, you could consider a good quality second hand one. I bought second hand but it was under a year old and was in immaculate condition.
Happy pram hunting!