If you want higher Tech, more power, higher tow ratings )in all models except the LE), a possible TBD (real, not a piece of foam) fix for the rear motor harness, than go with the 2026.
I also think the 2026 is an incremental update so it SHOUND not have any major defects but obviously it is unknown.
The current model Gen 5 was a clean sheet of paper with a new engine, new Manufactuing process, total new design from the Gen 4, which took a few years to fix.
If you go with the Gen 5 and are concerned with Tech such as autonomous driving, infotainment, and safety systems, the car will feel very outdated in a few years. If none of these things are important and/or you don't keep cars long term then certainly nothing wrong with the current Gen.
As far as differences to the hybrid system in the 2026, all past updates to the hybrid systems were incremental and did not cause any defects except for a few inverter issues that were issued TSBs so I doubt there will be any issues with the drivetrain.
I do agree with
@14v6 that the probable major risk is the software as this is a totally new design that encompasses the who cars operating system. I think ultimately it will be OK (it has to be as its the whole car OS!) but there may be some teething issues. At least Toyota has been conservative with software, unlike Tesla where the owner is the beta tester but we will see.
Where Toyota screws up is with fuel tank designs, coolant valves, too small or soft piston rings, bad harness designs, water leaks, sort of like a 17970s Chevy minus the piston ring issues, simply stupidity.