samsung phone keeps disconnecting from home network wifi.. unable to reconnect. keeps failing validation?

anyone else have this issue.. started about a month ago. before that i had no problem connecting to gateway wifi.. as of recently. frequently get disconnected and am unable to reconnect.. when calling tech support. they will refresh signal to my gateway and then my phone auto connects.. for about 4-8 hours and then gets disconnected again saying connection failed..  same with another samsung phone.  i had the gateway replaced so its new. i turned off my wifi and back on.,. on my phone. turned phone to airplane mode to hopefully reset connection. nothing. i can even be sitting right next to the gateway and still cannot connect. its an a32 5g phone. .again. up till recently.. its ALWAYS been connected wifi fine. but now all sorts of issues. HELP!!!