Possible bad repair work?

Toyota 2003 Matrix.

had a left front cv joint replaced at a Toyota dealer’s shop. shortly after, began to hear a whirring noise which I thought meant a bad muffler, but the muffler shop said it looked like a seal had been torn during the cv joint repair and transmission fluid was leaking, plus the noise I was hearing was related to that work.

went back to the dealer who said there’s a bad wheel bearing which they can fix for $400+. I had to remind them about the torn seal, which they offered to fix for free but did not take responsibility for.

my questions: is the bad bearing just coincidence? (the left front end has suffered some truamas and the boot was cracked) how likely is it they messed up the bearing if the cv joint installation was careless? should I get a second opinion? even if I did would it be worth starting an argument with the dealer? this is NY state.