Server and other (virtual) infrastructure management for nonprofits, lifestyle businesses, and hobby sites that have grown too big for managed hosting but don't

Server and other (virtual) infrastructure management for nonprofits, lifestyle businesses, and hobby sites that have grown too big for managed hosting but don't bring in enough revenue to hire a full-time sysadmin. It's a narrow niche, but I've got the local market totally cornered. Each client pays me a monthly retainer. I keep their servers, droplets, etc. patched up and respond to any emergencies. Most of the maintenance stuff is automated, of course. About $2K/mo, flexible but sometimes unpredictable schedule (log4j vuln on a Friday? Seriously?), friendly clientele, 6 years strong and going.