I can mark it up with a fee or by increasing the rate (or both, but I never do).

In this era of increased rates, obtaining properties that will produce a good return are harder to find and often involve quite a bit of work.  

From what I’ve read in The Economist, demand for “off-the-beaten-path” destinations has increased post-pandemic, as travelers seek quieter, less crowded areas.In my backyard, investors and homeowners alike are increasingly drawn to areas like Gilbert and Chandler due to their exceptional growth potential and quality of life.

And during inflationary times rental rates increase.

I'll focus on maintaining the property and optimizing rent increases to ensure consistent returns over the years.

Again, your time and energy is better spent increasing accountability and pushing RAD to improve their staffing with individuals qualified to maximize their portfolio at this time.....and in the future spend some time and money to perform adequate diligence before you invest passively. 

Your returns could be increased if you are willing to rent it by the room to individual students. 

I recognize this is not the sole source of return, but the other sources have their return increase with smaller equity position. 

For the next billing cycle they increased my charges by $500 and did not notify me of the upcoming charge.

Ideally a HELOC is used for less then a  year project where you can refi or sell to pay back the HELOC. 5 years is a long time, things can happen and if you reduce the cashflow on both properties you'll be increasing the risk and having thinner margins.