While I'm not entirely discouraged, I feel like I've invested significant resources (LLC, website, domain) without securing a deal that generates cash flow.Any advice or guidance would be greatly appreciated. 

Once the municipal/state requirements are all set, do a thorough screening for any prospective tenants, have a solid lease ready to go, and take move-in pictures to have on record for any security deposit deductions after they move out.

Securing loans with a low credit score is possible through private or HM lenders.

That would allow you to dock their security deposit more than just for the prorated rent for those few days.

You may or may not wish to fix it since its likely too late to charge the last tenant's security deposit for it and also that it sounds so minor that people didn't even notice it right away.

After securing a deal, your focus will shift to closing, finding tenants, and setting up efficient management.If you haven’t already, building relationships with local agents, contractors, and property managers in PA can save you a lot of time and hassle

Security systems are a giant headache for short term rentals.

From my point of view for event guest screening and security deposits, Superhog is reliable and integrates well for STRs and events, but you might need to adjust its setup for your use case.

Invest in a security camera—we had a break-in where someone lived in the house for days and stole appliances, which insurance didn’t cover.

Something almost always comes up and that helps you be realistic when evaluating deals, securing financing, etc.