That PSU sounds good enough to me.
Could be worth a motherboard firmware update?
and i would double check all the power cables.
It looks ike mangohud is an application to monitor stuff. I’ve never used it but you could give that a go - see if you’re ever getting close to the 750W.
Some useful stuff for some laptops - worth checking if you’re buying one for linux:
https://wiki.archlinux.org/title/Laptop
https://wiki.archlinux.org/title/Category:Laptops
Also this - i guess this is the inverse question though:
https://linux-hardware.org/