Hey @Cody Sears,
Good for you! 21 years old and already educating yourself on real estate. Love it!
Fellow house hacker here too! I think house hacking already puts you in a good position to start, so additional creative strategies will help even more.
You're on the right track! You can increase income by adding additional "rental units" whether that being an ADU, garage conversion, renting out extra living quarters, renting by room, etc.
You can increase income by short-term rentals depending on the regulations and profitability of the area.
My wife and I renovated our duplex to make it more appealing to short term renters. Now, we rent it out as a "mid term rental" with short term stays in between. It's been very profitable for us. The one unit nearly covers our entire mortgage.
I'd say some things to focus on renovations $$$ are the kitchen, living area, bathroom, design, and photos.
Good luck on your house-hacking journey. Please reach out if you need help with anything!
-Ant