As to “Baptism is necessary for salvation. “.
Jesus told the thief on the cross that he was saved. He was not baptised.
There is no record that Mary was baptised, but I imagine there is some “tradition” that says she was.
Baptism was, of course, something done to believers, involving washing. If it is necessary, then we should have to do it correctly. If it’s just a sign, it’s not as important.
Baptism is necessary now that there is a Church to which everyone has access (1 Pe. 3:21). It is not necessary when through martyrdom or some other insurmountable circumstance people desire to be baptised but are prevented from doing it.
It’s the same old same old here. Baptism is NOT salvific. It is necessary AFTER conversion but well, you know the routine here.