I'm in full agreement with @Colly18
on the swag camping, think the flat swag on stretcher under an awning is just so easy and fast.
Have slept in some very severe circumstances in recent years doing this, wind, rain, the swag kept me warm and dry
Most recent 13,608km 5 state trip this year, did that every night for 5-1/2 weeks, sometimes without the awning out, but I think off the ground on the stretcher is a very good upgrade
As for the OPs original question . . . I'd agree with @Ditch
there, grab anything that represents good value and just get out there.
Just about any 4WD will get you to some very nice campsites, away from the 2wd crowds.
Truly, $25k is a very good intro budget, but you could do it a heck of a lot cheaper if you wanted.
You need some vehicle and gear aptitude, but I picked up an old 88 pajero a few years back (2nd 4WD for a while) just a 3.0 v6 petrol, managed 13lt/100 out of it and not much more puttering along on tracks, and it would go some serious tracks for what it was.
$2500, or maybe it was $2000, can't remember now, but a more modern pajero in a diesel would serve you pretty well, and have some good low end torque as well.