The good news is our margin is good enough to not stress a ton about a single bad renter but I'd prefer we have a really clear picture before closing.  

Ok good enough. 

Get good enough at talking people into doing stuff and you never need to learn to do anything else lol. 

I've considered the following options but I would love to hear if there are more options I didn't think of:Install a formal exterior door in lieu/addition to the storm door (safest option, costs time and money)Leave it as is and rely on the internal-exterior door as a good enough protection (riskiest option, however the neighborhood in general is very safe)Leave it as is and don't market the sunroom as livable space.

It shouldn't take that long to get something good enough for your purposes.

For BRRRR to work you have to buy a fixer upper at a good enough price that you can significantly add value by rehabbing.

I’ve also tried multiple different cleaners and none do an overall good enough job compared to my current ones

There are many hurdles to find one that is in good enough condition to qualify for financing and also has an empty unit for you to live in too. 

Lots of options on house hacking and you can get fantastic low-down loan products (granted the property is in good enough condition).

Let me guess, this is not good enough for you either right?