meetings on sunday?

Context: I work at a startup, it's a pretty chill work environment, very flexible, hybrid model. Everything is great.

Problem: They take flexible work hours too seriously, I have meetings at 10 PM on weekdays and almost every weekend there's some work which they need the next day in most cases but apparently have to keep the meeting on the weekend with no prior notice.

I mean, i like going to office twice a week around 11-12 and coming back around 7, wfh when I have a few meetings that day but is it normal to work on weekends? and after work hours?

P.S. I've only been in this company for a month and joined as a fresher.

Now that I've put it down, this is such a gen z problem lol

But what should I do?