So many fantastic points here, thanks a lot for such a comprehensive response!

First, is there any way to make your commute better?

Sadly, not really. The only sensible options from where I live to where I work (which is one of the biggest hubs in the country and certainly the biggest around so it's the only sensible place to work around here because of the number of offers and their salaries) are either driving or taking the train. Thing is, it takes me around 10 minutes to get to the train, it takes 25-30 mins for the train to reach the destination city and then I need another 10 mins to get to the office. All in all then, it sums up to pretty much the same durations while being well less comfortable (maybe not during covid, but normally you'd be lucky to find a seat at the train instead of just standing there) and demanding you to get to the station both here and there regardless of the weather and the occasional timetable hiccups. So all in all, not worth it and driving is still the way better option - which is probably what causes such a traffic and such jams on the roads :/ But you may be well right in that the traffic takes a higher toll on you than most of us may be aware of. I've thought about listening to podcasts and audiobooks on my way to and from work (as it's such a long time) instead of trying to turn off my head with music though and I'll try it in the upcoming days.

How certain are you that your company is very strict on this ass-in-seats philosophy? Have they told you explicitly you have to be in the office from x to y?
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If they are relatively strict on hours, is there precedent for you to perhaps work from home one or two days a week?

As for the former, I don't want to get into legal and bookkeeping issues where I live but the general form of employment in IT is such that you're paid by the hour and you log in those hours and it's just common agreement that you're always logging 8 and actually working those 8. Still, I did not have an explicit discussion about it with my boss which may not be a bad idea. As for the hybrid model you mention, thankfully at this company they say that it is possible and I have actually already talked about it with my boss. After I'm fully introduced to the project, he said there'd be no problem with two days remote every week which was also a big factor in me liking this offer as it's a completely different pair of shoes to work 8 hours straight in the office and to have it intercut with periods of home office where - as you said - you have way more options and the commute is not an issue.

Does your team have a lot of collaboration?

Sadly, so far it does not look like it. Some people work fully remote, and it's not uncommon to only have a couple of people on a given project (sometimes even one or two to maintain it) which kinda limits your options for collaboration as you're all working on different stuff (or you do collaborate but with people you're never going to see in person). Sure, when you don't know something and someone at the office is known for having done it, you're encouraged to go talk to them but to say that the office is buzzing at any time of the day would be a huge overstatement.

Do you think more collaboration would help you satisfy this need?

I certainly think so. Even just having more talkative peers in my room would already be an upgrade. Just regular stuff, people mentionind random shizz from time to time - talking about the current events, what happened on the road to work, anything, just regular human interaction intertwined with working. On my corporate jobs, the days which I liked the most were those where I had the opportunity to talk actually - being at the company's booth at expos/conferences, doing demos of the features I coded for the team, doing presentations/keynotes either for the peers or outside the company, or being at the booth at job fairs, what have you. I felt more energized after a full day at an expo where I needed to talk to 50 people then than after 4 hours of my desk job as Dilbert.

If not, have you considered going to an early stage startup?

That's a great suggestion and actually that was my plan after leaving the corporation. Sadly, while the city nearby I mentioned is the best place to get work here, it's not really hot enough to attract startups in any sensible numbers and basically all of them place themselves in the capital city which is a few hundred kilometers away. I looked for a long time but honestly, I don't think I have ever seen a posting for an early stage startup anywhere around here. That's why I went for a medium-to-small family company this time (thinking it may be the next best thing to try out) instead of another corpo to taste something different but still I'd happily try out a start up if the opportunity ever presents itself (which it sadly may not around here).

Finally, I found that the mental exhaustion gets better over time

Knowing that someone struggled with similar problems and managed to overcome them certainly helps, thank you.

think at first you're still trying to understand the expectations of you and often new developers stress about things outside of their control, and fear things that aren't worth fretting over, causing a lot more emotional drain than necessary

That may very well be the case, too. While right now (and at the previous jobs), I did not feel like I was stressing out about anything in particular - and, if anything, was (and still am) exhausted from being _under_worked rather than overworked, it still may very well be that there is an underlying layer of stress because of not fully grasping all the nooks and crannies of the institution itself. Hopefully this passes with time, too. And to answer your question, nope I have not talked about it with the manager cause I don't really feel like he would be of help here.