I have a 2004 Discovery 3 which was specced in the highest possible trim at the time, I've been driving it off road for nearly 2 decades now and it's still absolutely fine. The only feature on it which is actually broken is the driver seat heating. Everything else, including the armrest fridge, works fine. 210k miles, no major repairs with the engine(4.4L V8 petrol). I had to get the chassis rustproofed few years back and the air suspension compressor replaced twice, but that's about it when it comes to "big" repairs.

My point is - I'd absolutely buy another highly specced, full of tech vehicle for offroading. Disco 3s were meant to be "catastrophic" in terms of electrical problems but I didn't really have many issues with mine. The only catastrophic thing about it is the insane fuel consumption(my long term average is 15L/100km, which actually at the current fuel prices is financially ruinous)