I've just left an exhausting role in the CS for one in another dept. It's equally busy but I really enjoy it, what was particularly exhausting about my old role was the toxicity of the team. My new team are nice, and I look forward to work on a Sunday now.
A couple of things I have in place to maintain work life balance:
I don't work past 6pm on any given day. I start at 8, usually finish around 5. 6 pm is a long old day for me. We don't do anything life or death so there isn't anything that won't keep until the next morning, everyone else starts at 9 so I'll get the 6pm ask done before they all log on.
I keep a flexi sheet so I know if I'm overworking and can stop myself working myself into the ground by stealth.
I never, ever cancel my leave for someone else's convenience
I won't have anything work related on my personal phone.
I block out time in my diary to get work done amongst all the meetings.
I decline or delegate meetings regularly (this depends on your grade of course, I'm G6 and have a big team I can delegate to).
Every Friday afternoon I go through the next week and sort out what meetings I need to be in and what I don't.
I always take a lunch break.
I make sure my team and manager know my boundaries.