with a  "FE 3080 and will be paired with a 10900KF"  , you should be ok with a 850 W gold or better psu.
Personally I like to be a bit safer & get more than needed w/ a few hundred watts above needs,...but you should be fine.

good luck , it's tough finding anything over 850W ( in name brands )  due to crypto miner farms

random_matt
Is it worth buying the supernova 850 gm? Many 850w units seem to shut down people's 3080 rigs. Wanted the O11D Mini, and this psu is the best available to me. It is a FE 3080 and will be paired with a 10900KF, not sure if I should just go ATX.

If you are getting the Mini, then you might be limited the SFX or SFX-L power supply sizes.  This will also limit you as far as options for high power PSUs due to form factor issues.  I'd go with the O11 Dynamic as you will have more space to work with and wont be burdened with trying to find the small SFX high watt PSU.  It's hard enough to find a high watt psu, its even hard for a high watt SFX psu.  The regular power draw of the 3080/3090 isn't the issue, it's more the power draw spikes that cause issues which is why you want to make sure you have headroom to prevent the shutdowns and such. 
 
The standard O11 isn't that much larger and should be more flexible as far as options to fit parts in.