None of the games have ruined my opinion of the lore, or the lore itself.

People throw around the word "retcon" quite a lot whenever a new Fallout comes out not knowing what that actually means. Fallout 76, for example, has about two-three real retcons: the information shown rewrites older lore. Otherwise it's just new information we are being told which is not always well written.

"Ruined" is a big word. There are some inconsistencies between each game, but nothing so serious that it completely changes the lore.

T-60 appearing out of nowhere was weird. Seems like saying it was manufactured post war by the BOS would have made more sense.

None of them have 'ruined' the lore, and the only one that pushed the boundaries too far isn't even canon

Shelter