I would leave around noon-1pm. You avoid many congestions. Gets you into OC close to early dinner. No rush to Check in, drop off and go back out to eat.
Still have time to walk the board walk without getting so tired.

Should be fine. That’s rush hour so will hit slowed traffic/back up at the Severn River bridge in Annapolis and the Bay Bridge, but shouldn’t be long or prolonged unless there is an accident.

Leaving at 4:00 will put you at the bridge at around 5:00 with regular Annapolis commuter traffic, which is not as bad as weekend traffic, but not great. Leaving at 3 or 3:30 would be ideal.

The bridge should be fine on a Wednesday night - you just need to plan around the rush hour traffic around your route.

We are going to Ocean city in the middle of the week and I am trying to figure out if it makes sense to take a couple hours off and leave around 4 (maybe could swing a bit earlier) or whether it makes sense to wait until 7 or even a bit later. Sorry if this seems like a dumb question but anyone have advice on what the traffic is like on a weekday evening?