Pathfinder 2e - How does it compare to other systems?

[Kurald Galain]

a good balance of investigation, exploration and combat.

Out of the systems you mention, the only one that has solid rules for investigation and exploration is PF1 / 3.5. The other systems all default to "yeah, just roll your favorite skill and make something up".

PF1 is less clunky than 3.5, although moreso than 5E. PF2 is more clunky than 3.5; it has a lot of little fiddly parts and tiny modifiers that you need to track even though they make no difference in practice.

HTH.