There should be other options, however with an LLC and fourplex - yes, DSCR is by far most likely to be your best option unless you do the heavy lifting with local banks and credit unions (and these are increasingly not great options for this type of stuff as they move painfully slow and are under lots of regulations and restrictions)2) I haven't yet reached out local banks, but seeing the quotes from brokers makes me wondering if Banks may be better? 

Option C (selling) simplifies finances and provides a large lump sum (~$270K), but triggers significant capital gains taxes, potentially increasing Social Security taxation and Medicare premiums.

Lender will make sure you dont open any new trade lines or have increases on your balances.

Improved DSCR: If a company’s DSCR has increased significantly since the original loan was taken out, it may qualify for better interest rates or terms, making refinancing advantageous.2.

They got us 10 DLC approved fast and we've been able to increase our texting volume to 1k texts a day with no problems.

There rental rate will increase with inflation and time. 

•Increased Security: Enhanced penalties act as a deterrent, helping to keep your property secure from unlawful occupation.

Do you feel, given the current state of the market, the risk is increasing in this type of investing?

If you don't have savings to get more property, the leverage would only increase and the risk so why risk something when you are creating a strong foundation?

Converting the entire property to a rental later allows full deductions but eliminates primary residence tax benefits, potentially increasing capital gains taxes on sale.