Congrats. Once you pay it off, you are just living off passive income then have a great legacy to hand off to someone/kids.
I was about 45 when I started in RE. About 3 years ago, peeked at 6 duplexes, 1 SFH next to a major university, 3 STRs. Goal was to have 25 rental properties in 10 years which seemed reasonable with just purchasing 1 per year. Once I hit 10 homes, the juice was not worth it anymore for me b/c my business income dwarfed rental income. I divested and now own 1 duplex, 3 STRs, 1 home on 3 acres, university SFH, SFH that I don't rent. I moved from lower valued rentals to higher valued rentals. The Cap rate is less but got tired of renting to the lower income population.
I don't think I will buy any more real estate unless something special comes up which seems to always happens. As I got older, time becomes more valuable than money. I rather play golf than grind on more rentals.