I haven't read all the posts since the OP
@413x but it's not exactly an unusual problem. People are taught that saving is "good", but often without any rationale underpinning it.
There are a couple of ways to look at it. Option 1 - you've got a really solid buffer that would get you through a wide array of the problems life might throw at you (needing a new car, wanting to pay for a private op, etc), and you decide "that's enough", and you spend what's left over from here on out.
Option 2 - you set a fresh goal. Depending on how much you spend, this could be the start of an amount that carries you through an early(ier) retirement. I know someone who's been laid off at 60, and now scrambling because they can't afford to retire until they hit state pension age. If they could take out £10k per year for 8 years, they'd be fine, but they haven't got it.
Personally, I'm more inclined to try to wind down my work (in terms of stress and hours) as early as I can, so putting cash away and investing it is a key part of that. I doubt I'll ever spend all of it, but I've got a very clear plan as to what it'll be used for.