OP, I think I may have responded to your other thread before. Glad you're putting boundaries in.
I work compressed hrs, in theory FT hrs but in practice easily over 40hrs across 4 days. Probably 45. If I worked 5 days it would be 50-55 no doubt. Tbh I could keep going and do 65 or more.
I had to get it right in my head that there is always more work to do. It will never stop. You need to stop.
Some problems, if postponed, will resolve themselves. That's great. No doubt they'll be replaced with new ones.
I have a zero inbox rule, only tasks not completed in any given day/week stay in my inbox. I write my to do lists in order of priotity and stick to priorities only, unless the world is suddenly on fire.
The lesser priority tasks get delayed or delegated. I'm working on delegating everything that doesn't desperately need me. Delegating is a big one - you have to do this. You're not paid to do everything by yourself, are you, and it's part of good management anyway.
I've also gone better at giving people a steer they need from me, but not doing the work for them. Let them learn.
I categorically do not reply to texts, messages or emails after 6pm unless it's really necessary. I had to change the meaning of "really necessary" in my own head first.
If I work late, I am offline on Teams so nobody sees me and I delay email delivery to 7am the following day so my team doesn't think they're expected to work my hours or respond immediately.
I am in a role that sometimes requires sending emails immediately even late in the eve because of external deadlines, but hand on heart, this is as rare as it has to be and if it happens it usually means all of us work longer and are online and we know what to expect.
In my experience, there is definitely a way to manage better and it's the responsibility of the managers to lead by example. It is 100% a cultural issue if they don't. It doesn't prevent you from doing the right thing, though.
Value yourself. Your expertise. Your time. Your health. You can't always wash off your hands in a senior role of course. But you're not supposed to be working for peanuts and sacrificing your entire life either.