Need advice on tire sizing

Hello gents,
I recently acquired a 2021 Platinum with aftermarket wheels on it. I would like to swap out the wheels first something else. Currently it is sitting on some Fuel Maverick 20x9 with a (i’m guessing +20mm offset). Size 275/60-20. But it rub front and rear flap at full turn. With both flaps removed minimal rubbing. But still rubs.
I would like to change the wheels to a Fuel Tech +20mm offset. Either in 18x9 or 20x9. I haven’t decided and really dont know what would the benefit be for one over the other.

Tires interest in: Falken Wildpeak A/T4W

Please recommend best tire sizing that will not rub with both flaps reinstall.

A: 18x9: best tire size, zero rub
B: 20x9: best tire size, zero rub

stock height. No plan for raised or leveling kit. Will stay stock.

thank you

 

Have you looked through this?

https://www.tundras.com/threads/official-tundra-wheel-and-tire-setups-pics-and-info.95/#post-858

 

thank you for the link. I will start reading.