@aveltens did that as an experiment and got quite far, though it’s not a simple thing to do: Discussion: Solid vs. ActivityPub - #34 by aveltens
More details in German on his blog: Mit Solid nach Mastodon posten, geht das? | Datenwissen
But the summary is: you can get quite far theoretically, but it’s only a proof-of-concept and it’s not clear how well it’ll work in practice. I also don’t expect it to work with every Solid server.