Really depends on how you intend to use the vehicle.
What are your plans with it?
How long do you plan on keeping it?
What's the goal? Daily driver, overland build?
What models exactly are you looking at on both sides? SR5 premium 5th Gen vs base model 6th Gen?
Sounds like you're looking at a 6th Gen SR5 as well? If you're looking at a base 2025 SR5, it's not all that impressive compared to the premium models. I'd honestly stay with a 5th Gen over a 6th Gen if you're looking at non-premium 6th Gens.
The new motor, even on the base 6th Gen non-hybrid, is much quicker than the old 4.0L V6 1GR. If you're after speed for highway use, the new generation is the move.
What exactly are you considering and what are your goals?