I wouldn’t look at a paid off Mello Roos as a negative when selling. I’d actually look at it as a huge positive in an up market like this. I actually met a few people that also paid off their MR and they were able to use it as a big selling point when selling as the buyers could roll up the extra cost into a mortgage vs. shelling out cash out of their pockets each year.
If it’s taking you forever to rent then it’s either priced too high or it’s not as appealing as others. Ideally you’ll want to paint rooms neutral colors, have clean carpet, etc.
Always better to lower prices and keep it rented. I own a ton of rental properties and a philosophy I had from long ago is a rental day is much like life. Once it goes by you can never recover it again.