Also depends if you're gonna OC it
750W is sufficient enough, but given the state of crypto mining where PSU supply may have been affected, its not a bad choice to also go for 800W or higher, which also gives you some more headroom. Cryptominers buy PSUs too.
So 750W if you can get it, or go for higher wattage whichever is available.
I had a 2070super an i9 9900k. It ran on a Seasonic Focus gold 80+ gold for a year and a half. I used that psu for the 3070 about 2 weeks also before i got a new psu. If i am not mistaken the 3060ti has 600w as recomended psu. So yeah your good