Brian I will speak from personal experience and I am much younger than you but I started when I was 22 years old and I made every possible mistake. I would highly advise you to not use HELOC to finance a deal. Reasons are obvious, if you are borrowing against your primary residence.
If I could do it all over again, I would: find a hard money lender (most have kind of the same terms 90% of purchase, 100% of rehab) to fund your first deal and I would do a flip to start and get your feet wet. Nothing crazy, something in the $130-$140k range that needs $50-$60k rehab and you can sell for $250-$260k. You can find those all day specially in your area and you only need to put 10% down which seems doable given the description of your finances.
Flips are a great way to get you started. I would be heavily invested in the entire process from start to finish, including the renovation (from a management perspective and of course paying visits to the site and talking to all the contractors). That will help you build confidence and a nice understanding of the process.
Do not follow the advice of all these instagram "gurus" telling you how they flip 50 houses a month from their couch is pure BS or how they do 10 BRRRRs all over the country. Not happening. I have been involved in many construction projects all over FL, OH, IN, NY and NC and not a single one I could have ever pulled off from my couch. It takes a lot of patience, strategic financial planning and most importantly a reliable and punctual team to finish on time.
After your first flip, you can then figure out your strategy for a BRRR or even see if that's the route you want to take. These type of deals usually require much more work because you have to take into consideration the 70% rule and other stipulations. If you are planning on BRRRR, you can always find a lender that will give you the funds for purchase, rehab and then month 3 -6 you can refinance the loan with the same lender with a product for rental purposes avoiding you using a HELOC.
As far as Airbnb, I owned and managed 27 units at one point, in South Florida. It was a mission to say the least, and you definitely don't want to get into the hospitality business unless you know what you are getting into (seems you have a busy schedule given your strong W2s). People will say oh just hire a property manager, sure, but they will send a handyman or contractor to resolve the tiniest problem and will end up cutting into your profits big time. Not to mention Airbnb has been declining over the past year tremendously, and user confidence has deteriorated and is continuing to do so. The Airbnb market is highly, highly saturated and will only get worse. I see condos that retail for $2M renting for $250/nt. That is absurd from a financial standpoint. I am afraid you will end up getting exhausted with all the problems guests bring, and the bills from the property management company will not make much financial sense at the end.
Also, one of the reasons I really like using hard money to do flips is because you have that extra peace of mind that you are not setting up yourself for failure since they are also doing their due diligence to make sure they minimize the risk on their end, which ultimately benefits you.
Connect with a good realtor that can find you a great flip and start there, use the lender's money, leverage your cash. Learn in the process. Rinse and repeat.
Good luck with your endeavors and reach out with any questions!
