AMD drivers really dont suck anymore its just an age old stereotype thats never been given up by the general community. Its also a lot of confirmation bias. Me personally ive run 2 Nvidia GPUs in valorant and 2 older AMD gpus being the 560 and the 5500 both AMD gpus were completely fine and i never faced any problems. If anything once i switched to my 970 and then 1650 (1650 has less problems) ive been getting a lot of stuttering, crashing (really REALLY bad on the 970), and sometimes even artifacting + invisible characters (tho tbf this only happens when i have ridiculous packet loss)
Both are fine honestly if you buy the newer ones. Valorant is coded well enough to work on both as long as you dont mess with stupid settings that dont need to be touched.