same problem, but with a twist - my wife’s iphone 8 with 14.3 barely or doesn’t connect to our wifi network on 5g or 2.4g. I have a samsung S9 and no problems. There does seem to be a nuance of the security ability of the wifi equipment for us. If the wifi router/booster supports WPA 2 AES or WPA 3 security it seems better, and when it doesn’t support that it seems much worse, but my android phone has no problem working around this either way, so it is for sure an ios problem. We’re looking moving away from IPhone as well.