I am also - and always will be - a joplin-user and thought about outsourcing the tasks/todos. Was looking for selfhostable, opensource alternative with a mobile app (iOS) but it was harder to find sth than i expected.
These were my candidates:
SiYuan -> selfhosting does not work with apps (web only)
Anytype -> did not get the server to run (there are a lot of variables in the dockercompose.yaml und .env)
Affine -> there are no mobile apps at the moment
Logseq -> no selfhosting
Now i try to get Appflowy to run on my server: https://github.com/AppFlowy-IO/AppFlowy-Cloud/blob/main/doc/DEPLOYMENT.md
BTT: For shoppinglist i use kitchenowl, for collaboration mostly nextcloud.