Handling of ics or vcal files

I didn't use any of them, but you could try to convert the calendar events to Markdown by a custom script (GitHub - hmerritt/go-ics-to-markdown: ICS->Markdown | Convert a calendar ICS file into a Markdown table / GitHub - fdagner/ics-to-markdown-for-obsidian: Imports calendar entries from a date range into Obsidian's daily notes via ics links) and then import to Joplin.

Would be a good fit for: