Alternative to Confluence

Hello everybody, I started using Confluence more than 10 years ago when it was $10/year for 10 users. Then Atlassian decided they don't need small businesses/home users and removed on-premises licenses. So, I use Confluence 8.5.6 as the latest available for my license since then. I like it but... Outdated JDK (11 I believe), no new features, security concerns, all that stuff, you know. So, what is the best free (or reasonable charged, lifetime license is preffered) alternative to Confluence for small home/business use? Simple migration is also one of the key factors to consider. Thank you.