The cabinet under the sink had water damage to the base, and I have the option of just repairing that and painting the inside of it.

It comes with the territory like a water leak, roof damage, etc..My $0.02 ...

With that said good pms can make you more money than you pay them by keeping rents at market rates, quicker turn around times, and forcing tenants to be responsible for more of the damage and maintenance.

Professional cleaners (Molly Maid Company) says it can't be cleaned.Has anyone had experience with damage that can't be fixed, but maybe doesn't warrant a brand new appliance?

They can send you photos of any damage so you can submit claims.

I plan to give my tenants a proper notice to inspect the apartments for any damages negligence.

Cons might include increased inspections and regulations, potential for property damage, and the possibility of dealing with tenants who have more complex needs.

Additionally, you must notify your insurance company to adjust your policy to cover short-term rentals, ensuring you have appropriate coverage for liability and property damage specific to Airbnb operations.

The damage to the sheet rock in the basement wasn't bad, and I set up a bunch of fans and ventilation in order to prevent mold from growing.I went to check on the first floor apartment to see if there was any damage and luckily there wasn't.

If they deliberately do something to damage the AC, then yes I would expect them to pay for it.