Are you looking to pop into the cc bonus game (getting cc because they have a good bonus with the intention of cancelling/downgrading after 1 full year before paying the AF again if the card doesn't make mathematical sense to keep for another year)? Or are you looking for maybe a new card or two to supplement your current purchasing? If you aren't interested in bonuses, lean into the eco system you have to earn more points. So with Chase that means picking up something like a Freedom or Freedom Flex for 1.5x UR back on everything or 5x rotating quarterly categories respectively and then transferring the points over to your CSR. You'll make a lot more dough with your spend if you start focusing on a bonus here or there though...
And yes, Lessor of Real Estate definitely qualifies as a business! If you don't have a separate entity set up for doing it that makes you a sole proprietorship and you use your SSN in place of the EIN (and it gives you a more legit business than like half of us here who tend to be really optimistic about our ebay potential

...). If you don't have a DBA the name of the business is just your name. The nice part about business cards is Chase and Amex biz cards don't show as new cards on your credit report so you can hit them without affecting your 5/24 status! They will hard hit your credit which will whack it for a few points but it will recover. I recommend starting with the Chase biz card that has the highest bonus right now. Do you have a Partner? If so once one of you get any Ink card you can refer the other and then go back and forth referring each other to the other Inks. Recommended pacing is space out every 3-4 months. Chase is getting stingier on approvals these days but you're basically fresh so you should be good to go.
Is the DVC purchase something you can use cc's towards? Amex has a business platinum card that you can sometimes pull bonuses of up to 250k points for but it has a hefty $20k spend. I wouldn't slam the card for $20k right off the bat (or you risk getting a financial review where Amex will ask for an IRS transcript copy of your taxes to verify your income) but figure out a level you feel safe at and you could put away a nice chunk of that spend during your dvc purchase. Amex has multiple transfer partners so if biz class flights are something you're interested in it might nice to have Amex and Chase points to work with to try to piece something together (never transfer points unless the flights are available).
Random- DoC keeps a nice list of best cc bonuses for personal and business use
here. Feel free to pop in here when you're about to apply for something if you have an specific q's or concerns or just want to make sure their isn't anything weird to be aware of (like Cap1 biz cards usually, not always, show up on personal credit reports and would therefore affect your 5/24 status- we are fountains of random info like that lol). Keep in mind Amex bonuses are once in a lifetime, once you've had the card you can't get a bonus on it so you want to make sure Amex bonuses are good offers when you go for one. If you want you can join our private reddit group
here where we share "support links" but no pressure if that's not your thing!