Should I be able to open DEVONthink as a document provider in apps like Textastic like you could do in DTTG2.1?
You may have to enable the option in the application of it’s not showing.
I believe changing an option in Textastic is not needed. For me, it works well for opening files in DTTG3‘s database with Textastic‘s „Open“.
Only a whole DT folder cannot be used as „external folder“ in Textastic, which seems to have to do with DT saving its data in a database and not a file structure (was discussed here on the forum).