As a lender, I recommend you stay put @Leah Burns - here's why.
1. You mentioned your credit is not great. Instead of repairing the house (that already has a tenant in place), repair your credit. Work on your debts, dispute past delinquencies, and get yourself to a 740.
2. Save up your cash. You will need this cash for future purchases and closing costs (even if you use VA again, you'll need to pay an EMD). Keep this on hand for when the next opportunity arises and learn more about investing
3. Since you guys used your VA loan, you have a major advantage now that you have a tenant in your property. PLEASE make sure your taxes (on your Schedule E) show that you've been renting this out. Lenders will look at your Schedule E to determine (VA loans) if you have experience as a landlord. If you have 2 years of experience as a landlord using a VA loan, you can use the existing leases as income on multifamily properties to help qualify you for the loan. Conventional loans require 1 year.
4. Feel free to drop by the house and make some inexpensive repairs on your weekends. Learn to be a landlord and deal with collecting rents, handling issues, and being comfortable with the process.
5. It probably doens't make sense to refinance. You likely have a killer rate from 2020. Refinancing right now will not only raise your principal, but there's a good chance you will be in the mid-5's to mid-6's. Keep your cash, keep your low monthly payment, wait to access the equity when you are in a better financial position.