Not office hours? No contact
My work life balance is quite simple. If it's not office hours, and not some agreed and planned well in advance exception, then I'm not available.
The company I work for (US corp, but I'm based in UK), took the decision some years back to no longer provide company mobile/cell phones. I was also hot desking at the time, so no desk number either. So for years now, I've not had a 'work' phone number, and I don't give out my personal number to work only colleagues.
This means for years now, if you want to talk, you had to Skype me (desktop app only), although we've moved to Teams now, same rule applies.
Also as no company mobile/cell phone is provided, I also won't install work Office/Teams etc on my personal devices, so access to Teams and email is via company provided laptop only. (We do not have BYOD).
You can send me emails, or messages on Teams, whenever you want, just don't expect an answer outside of office hours, or when I'm on leave!