Macbook 2017 connecting to new Wi-Fi but drops every few minutes

Hi, we changed broadband providers yesterday, my Macbook Retina 12-inch 2017 running Big Sur is initially connecting to the network OK and running internet but loses connection every 5 or so minutes... all other devices including iphones and other laptops are connecting fine so assuming no problem at Wi-Fi provider end.

I have spoken to Apple who have suggested resetting the DHCP, starting in safe mode, altering DNS settings, starting in safe mode, forgetting all networks then re-logginng in, none of which have fixed the issue! Apple are suggesting takining my laptop to a store but not sure if/how that would help without access to my Wi-fi.

I wondered if anyone had experienced similar, or had any ideas? thanks!