3K MRR here after running for 5 years and the projects are on autopilot too. Growth is very slow, zero marketing efforts made on my side. I think it's hard to get more value from this product though, hence why I focus on other ventures.
Not that many support requests.
A few customers racking up bills for thousands; 3-4 never paid and I didn't persecute them, the rest did.
You were lucky on chargebacks resolution, generally the b**rds always side with the scammer customers trying to get service for free. I've tried arguing many times but it's completely useless. That's also why I'm afraid of doing a project where my margins are smaller. Plenty of them then try to resuscribe Right now hosting is 50$ per month, so if someone steal access to my product I don't care much.
Merchant of Records saved my life, F*k Europe VATMOSS, Sales Taxes, GST and every other crap governments add just to kill small businesses and make them flock to Amazon. Paddle support is pretty bad, I wouldn't go with them if I would do it all again. Probably I'd try LemonSqueezy (now acquired by Stripe).
Selling the business: I was offered money for the business but I don't think it's worth it, given how much it's on autopilot.