I’m Planning a trip to Montreal in the spring, what are some recommendations and advice?

Hello, I am from the states. I’ve never been to Canada let alone Quebec, but I’ve always wanted to visit and Quebec is very intriguing to me. Montreal looks beautiful.

I am looking for

- Good food (I am pescatarian so vegetarian places and seafood places are a must)

- Good museums and historical sites (I also love a good science museum)

- Good shopping areas that aren’t too touristy and overpriced

I found a pretty decently priced hotel near public transport. (Hotel Manoir Sherbrooke)

And I’ll likely be flying Air Canada

Also how is the public transport there?