Whataboutism. Bitcoin does not need to be proof of work. It’s horrendously inefficient.
Bitcoin does need to be proof of work. any system without that isn’t bitcoin.
ethereum also has no supply cap. they are different technologies almost entirely.
i would not call PoS bitcoin anything except p.o.s.
there is still a pow blockchain running for ethereum, and there would be for bitcoin, too, and that is the blockchain i would call bitcoin.