for gaming I would prefer the 16:9 144Hz monitor + Gsync.
Even if price is of no issue? Have you gamed on an ultrawide?
yes, now a days more games are supporting 21:9 but i'm not a fan of ultra wide. i feel even though you have more FOV you don't necessarily get to use it to the max. i find myself moving my head too much. but it's personal preference.
for FPS i would not prefer it, for RPG games maybe, but the lower refresh rate and higher requirement on the card makes me still prefer 16:9.