Bells and whistles innit.
IME the lowest maintenance bikes have the fewest features and components to be damaged by the environment you use the bike in and/or overzealous cleaning regimes…
The answer to the OP’s issues is a rigid SS of some sort… Obviously it’s not the ‘right’ answer, but if you really wanted a MTB that will manage year round use in the UK, that’s the starting point.
Every additional bit of gearing, bounce, uppy/downy post or other gadgetry inevitably adds to the list of “stuff that will probably fail one day”
Not that I am against toys, but you really have to factor at least an idea of failure rate into your decision about buying them, and after a while a “winter bike” can start to look like a rather sensible N+1 justification…