You'll probably find everything you want as a tourist still available. Including diving, though some dive centers may be closed. Most staff are willing to work, but mandatory overtime rates are very high and many operators without pre-bookings just won't open.
Bugs are virtually never a problem during the day, except when there is no breath of wind (which is very rare). They are virtually always a problem around dusk, which is the time to retire to your A/C room for a shower/duty free booze/snooze. If you're out-and-about wear (lightweight) long trousers that close around the ankles, open sandals if you're going to be walking in sand (unavoidable here) and carry a can of "Off!" with you. An hour after dark all the bugs have gone.
Swimming near the beach is possible though only attractive in a few places. WATCH OUT for boats, even if you're inside the line of markers delineating the "no wake" zone. There have been unfortunate accidents, including recently.
Much of the sea front around the town is either a sea wall with no beach, is unusable because of boats & docks, or is superficially attractive but has extensive sea grass starting just off the beach. Eels have been known to lie in the sea grass, and they don't take kindly to being trodden on.
If you're well away from the town area the issue of boats becomes less significant, and the beaches more pleasant anyway.
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