Doubt about buying 750w PSU

I recently bought a 7800 xt and was told to also upgrade my current PSU to a gold rated 750w. I bought both and I am now doubting myself because I also want to upgrade my motherboard and cpu since they are old (ASUS Prime Z370-P and Intel i5-8600k). What I worry about is that 750w won't be enough for my future upgrade.