Ask HN: Next steps for my SaaS business?

Long time HN reader here, first post (ever!). I need some advice on what I can do with my SaaS application and companion Android app (https://www.servicekit.io). A little over 4 years ago I started building this app in my spare time. Long story short, I partnered up with someone (for funding) and outsourced the application to a remote team and over the course of 4 years have 4 users (2 paying). I acquired these users in the first 2 years, and the last 2 years I haven't been putting much effort into the business at all. Growth has stopped as a result. Collectively, my partner and I have invested approximately 85k (USD) into the business, and the paying users are covering the monthly expenses. It's completely passive, the paying users don't bother me at all. The app is also rock solid, haven't had to touch it in I can't remember how long.

My partner was a "silent" partner and just provided funding. I built this app from the ground up, did all the cold calling, acquired my customers, and basically got it to where it is now (its been the most valuable experience in my professional life by the way). I've lost my passion for the app, and my partner and I decided we need to see what our next steps can be. What are my options? There's a lot of competitors in the space, and pricing is all over the place (from freemium to hundreds of dollars per month). I've considered selling it, to taking on another partner who would help take it to the next level.

Any advice would be greatly appreciated!