Yeah, foam isn't a great option for cross platform (mobile).
If you use an iPad and have your notes in a GitHub repository you can use code spaces which is the vscode editor (I'm not sure if the extensions will work though)
For me it was about getting the notes in one place where I could manage them as I would in my text editor.
I always got frustrated with the implementation of Markdown and no being able to manipulate the text as I would in a .md document.
I have lost some functionality that Notion had, like for Kanban boards and such but being able to manipulate the plain text is where I want to be.
The only downside I have really is that I'm tied to using a VS Code now for writing notes, if I want to go mobile I can use something like GitJournal on android and make changes there, and there's now code spaces in GitHub so I could in theory use a code space in a tablet on the move, but none of us are out and about that much these days
Only appears to be working in iMessage currently