Given the team they had and again coming up short because of QB play or lack of QB play, I don't think they mess around with going with either Trey Lance or Purdy. I think they go get a veteran.
Brady is the one who has been rumored. But I would be fine pulling 41 year old Philip Rivers out of retirement and having Purdy back him up. Shanahan's offense requires a QB to be a ball handler, quick decision maker, be on time, have a quick release, and be accurate 20 yards downfield. They don't need a Trey Lance or Daniel Jones. They need a guy to get the ball quickly to Deebo, CMC, Aiyuk, and Kittle.