Where will you be working? That affects the shortest commute for you. There are liveaboard
spaces from Chula Vista, at the bottom of the bay, to Shelter Island, at the top.
What kind of boat, and what size? Power boats are common, and getting cheaper due to the high cost of fuel
(making them more like crashpads than vessels). Monohull
sailboats are also pretty available these days. Multihulls are more of a challenge due to availability of end and side ties. Big boats pay a premium for dock space. Moorings are available, but not necessarily convenient or comfortable, especially the "Rock and Roll" moorings off Shelter Island.
Technically, there are no liveaboards allowed in Mission Bay (discrete silence, here).
The cost of renting
a slip will be generally less than renting
a much larger apartment. Still, the act of living in a space slightly larger than a closet, is familiar to you, so you'll probably adapt well.
Some yacht clubs are soliciting memberships for smaller boats, and they also have liveaboards, so you can check those out, as well. Good luck!