I’ve always enjoyed teaching (until recently but that’s an anomaly.) There ARE drawbacks but let me talk you through the good stuff first 
Firstly and most obviously, it pays well, possibly not compared to what you were used to previously, I don’t know, but whenever I idly look at other jobs I realise I am comparatively well paid. Plus good sickness benefits and pension contributions. If you pass away (sorry not very nice) your children will have some money while they are in FT education. I know these things were better in years gone by but they are still worth having.
I’ve been teaching a long time and when I first started it was really hard. Coursework then gave way to Controlled assessments and so much stress and marking and kids behaviour wasn’t the best. I’m not saying it’s all rosy skies now but the 100% exams do at least put the onus very much on the students and they reduce marking and workload.
It’s obviously a relatively short working day (it is an exhausting and intense one though, my partner does get a bit fed up with how tired I get sometimes, I don’t mean with me personally but I just mean to illustrate how other jobs can be different?) and you do get the holidays. I’m pregnant at the moment and at least I know in my family we are sorted for holiday care!
While there are DEFINITELY some exceptions most teachers are really nice, kind people and lovely to work with. I have some lovely friends from schools I’ve worked in and when we meet up we always have so much fun.
Behaviour is a funny one and I can only give you my opinion, bear in mind this is very much just my view! I rarely have problems with behaviour now, although I definitely did as an NQT! That was partly because I was 22 and looked like a stupid teenager but also I’ve learned a LOT about myself, to be honest.
I used to think rigidly adhering to systems was the right thing to do and I used to think if I showed kindness I’d be taken advantage of ... I cringe a bit. I was fighting a losing battle.
Now I think I’ve learned that fundamentally what pins it is respect. I am very respectful towards students and to their families. Personally I do think you catch more flies with honey than vinegar and if someone is a problem I try to think about how I want to change their behaviour not just punish it. You also learn so much about being proactive not reactive - sorry that’s such a wanker phrase but it’s true, you know you have a noisy excitable class so you plan calm, focused activities, you know James in Y9 will be difficult and arsey if he can’t do the work so plan something he CAN do and then You have an opportunity to praise him ... It’s tricks like that. Early in my career I heard the phrase ‘you can make your own weather’ and it’s stayed with me.
Some schools are really, really strict. Personally they aren’t for me - I don’t want to be getting on a kids case over something petty like the wrong colour socks or forgetting a pen once. But by the same token you do need to have a school where there is a firm discipline policy but one that’s ultimately fair and reasonable and gives you autonomy and professional judgement but also supports you. But I know some teachers love working in very strict and rigid environments like Michaela: I’m not saying for a moment I think they are ‘wrong’, just not for me!
Children (even the big ones!) are really lovely. I had a really hard time when I was a teenager and for me it’s been massively healing in many ways, going back and actually trying to help. I laugh loads in schools, kids are so funny (often without meaning to be!) and they can also be very protective of you as their teacher. Something else that stayed with me from early on was someone saying that no one remembered who the Olympic gold medalist from even the last olympics were, even though he or she was top of their field, but everyone remembered a really good, helpful teacher.
Downsides - so yes, people leave for a reason!
Teaching isn’t as secure as people believe it to be. The problem is that HTs have a great deal of power - capability can in theory be started on the back of one poor observation. Bullying in teaching is unfortunately an issue because of this.
As I mentioned above the actual day is exhausting.
It obviously isn’t flexible - obviously you’ll know this - but again this is where I think my partner sometimes wishes I wasn’t a teacher, he’d love to just go to Greece for a week now (Covid aside, I know!) but we can’t.
I can’t put this politely - there is a lot of bullshit and that can get really annoying. The current fad is knowledge organisers. Before that it was formative assessment, then APP (I think) ... there will be others. I try not to visibly roll my eyes!
For you, one downside and a big difference in recent times is when I was at school we all did french with the option to do Spanish or German. Now Spanish seems to be the default language with french as a second one. It could well be worth getting a qualification in Spanish too. Remember just to GCSE so you probably could manage it.
Good luck, I hope this was helpful.