In decent nations, an EULA is considered an attempt by the seller to, after the purchase, change the terms of the implicit contract which was the purchase, so it’s has no legal standing whatsoever.

Absolutelly, the seller can set contract terms before the sale is done (and even then there are lots of limitations to avoid things like bait & switch, so it usualy has to be pretty clear and upfront and there are certain rights that a retail buyer simply cannot loose, even contractually), but never after the sale has been done.

EULAs only have legal standing in a few places, including a few States in the US.