Yes, ten years ago when I already spoke/wrote perfect English on paper but didn't have much experience talking to actual people (CS GO voice chat doesn't count) I often had times where what I wrote in English would have been a perfectly reasonable way to express an emotion in German, but the other person found it odd. Of course I didn't literally translate a German expression 1:1, that would not be the yellow of the egg (ha). Instead I struggled to for example with a general way to acknowledge the feelings of the other person, I always got confused responses since the words in isolation were grammatically correct and in German would have been empathic enough, but the, I wanna say, "social weight" of the words was actually way off. Again, I was already speaking perfect English back then, but with no real-world experience. Societal differences may have also played a role, as Germans are generally regarded to be more cold than the English or the inhabitants of the FSA (Facistic States of America) plus me having autism didn't exactly provide for a good basis of understanding the weight or intended emotion of the words I chose back then. Now I think I have a good understanding, but I have to conciously "translate the emotion" as well as the actual language. So yeah, I completely get you.

Never. You just need to learn the social weight of the words you use in the context your in. I’ve heard 10 year olds shouting the F word in class and their teacher never batted an eye because they didn’t speak English there. Caught me off guard, but nobody “gets” that it’s bad. It’s just a funny sound people say a lot in foreign films to them. Someday they’ll embarrass themselves in an English speaking country and figure it out.

It might have happened, but people have not called me out on it. I keep far away from swear words while learning a new language.

Something I am struggelig with however, is being seen as less intelligent and less capable because I am speaking with an accent and/or bad grammar. Constantly being seen as less valuable.

In some capacity, yes. English is my second language and I noticed it feels different (sometimes) to say or think something in it as opposed to my native language.

I found that sometimes my brain prefers thinking something in English because it feels more detached than doing it in my native language.

OMG YES!!! I thought this was just a me thing. It happens to me all the time with English and German

No. But I find many things sound natural to me in English (2nd) while sounding weird in my native language.

It's not the matter of translation or phrasing, instead it's that I am not used to discussing some topics in my native language, going to the point of feeling uncomfortable to say or write.

No, if anything I sound warmer, because most of what I know is social niceties.