Lots of options all with varying pros/cons
*New LD Defender
*G Wagon
*Used FJ
*Nissan Armanda/Patrol (infinty QX)
*Toyota Land Cruiser LC200 (Lexus LX570)
*Jeep Wrangler
*Ford Bronco (6th gen once you can get one)
*Any range of mid of full size pick ups
The obvious answer is a FJ or Tacoma as those are based on the same platform as the 4runner, I am assuming the Lesux GX460 is out as its essentially a Lexus 4runner/Prado 150. Tossing all those aside -
If I was to replace my 4runner today knowing what I know now and where I am at in life I would expect I would gravitate Towards the Bronco or Raptor. I really like the Options/Look of the new Broncos and am Renting a Raptor for a week shortly to see if I could live with the size. I am in NO rush to replace the 4runner and do not expect to even seriously consider it before 2024 and at that point hopefully the next gen LC and 4runners are out to cross shop my above options.
That said, I have learned Toyotas last longer then I will ever want to keep one - I will be at 10 years in 2024 and the damn thing is barely broken in (<80k miles now) and will be around 100K or so then. The rust (currently not bad for living its life in MN/MI) will get it long before the drivetrain dies. My point being a Ford or Ram or Jeep may not be as reliable as the 4runner or a LC but I am not dragging my family through the Congo and have never been anywhere in the States where my life would be on the line with a break down (expense and annoying yes) and if I was going somewhere remote like the Needles I would have a sat phone / Emergency beacon regardless of if I was in a Fiat or a Land Cruiser
*Edit the Correct answer is a LC200 but doesn't mean thats what I would do