@Jake Arnold
You've really got a TON going for you and sounds like you can stack together multiple strategies which will ultimately really accelerate your growth.
1) You are willing to move
2) You are willing to rehab yourself
3) You are willing to house hack with roommates
4) You live in/near markets that cash flow
You are perfectly setup for owner occupied house hacks of multifamily properties with a possibility to transition to BRRRR or live in flips once you have enough capital.
I firmly believe it's important to play to your strengths and what your market(s) allow. Using the above strategies, you should be looking to purchase a property every 1 to 1.5 years. I know a HELOC was mentioned or taking from retirement accounts but I wouldn't because a HELOC requires equity (i.e. larger down payment) and/or appreciation and it sounds like you won't have much of either to maximize growth and your cash on cash return in your cash flow market. And you're way too young to forgo interest investment compounding so I'd keep contributing enough to retirement accounts to get the match and let it ride. Always good to invest in multiple economic sectors.
As long as you are buying duplexes and larger, you won't have issues with vacancy and you'll be able to pay the mortgages. You will have to watch out for your 10 mortgage limit however so either find a portfolio lender or 1031 exchange into something better.
Keep going for as long as you can. This strategy typically only works for young singles and once you get married and have kids the "move every other year thing" isn't feasible. You've got 5 to 7 years of working super hard and growing your portfolio like crazy before you'll need to switch strategies. Best of luck.