Any advice on building a sustainable budget would be appreciated!

Sadly, I don't know what the solution is, but I can guarantee that if more STRs get shut down there will need to be an increase in taxes coming from somewhere. 

Leverage to a point where it is sustainable and can get you a good night's sleep is what is the best way to use it.Yes, with over leverage you can try and grab as much, but then, the risks are higher.

Certainly trying to build something sustainable! 

If I recall, the investor had a high-paying W2 job, lived very modestly, and put a lot of her disposable income into buying and renovating properties for a sustained amount of time.

Firstly, various government policies and programs aimed at promoting homeownership can sustain or increase these rates, even amidst rising prices and interest rates.

They are allowable per code here but are generally looked at as temporary solutions and to be honest you can get a ring crimper for the price of about 4 or 5 press on fittings... thus cheaper and more durable/leak free to go the crimp ring route..

Sitting there and filling out an application is time consuming and frankly gets you into more problems than solutions. 

To generate a sustainable amount of income from having at least 3 to 8 doors in order to become a full time entrepreneur.

If you're looking for a passive solution (or wanting to unload pieces of the process then technology is your solution.