Is my power supply enough for my rtx 3070 ti 8gb

I am trying to figure out why when playing maybe more ressource-needy games and watching YouTube the fans or my 3070 ti often go into loud overdrive and screens black out. My guess: it's the power supply?

I have a rtx 3070 ti 8gb, running on a Corsair RM550x 80 PLUS. Is this enough?

Also concerning cables: the 3070ti has 2x8 pin input but the cables conjoin to a single 8pin that goes in the 6+2 slot on the RM550x. Is this correct?

I am honestly not much of a builder and bought this pc used that way. Please be gentle :).

I7 6700K Intel Prozzesor 4.1 Ghz 32 GB Ram NXT Watercooling