Rated 5 out of 5 stars

For users mentioning the html attachment issue:

This and similar Addons only supplies the url, Thunderbird wraps its template around it and inserts the whole thing into your message

technical details:
https://gitlab.com/joendres/filelink-nextcloud/-/issues/238#note_383881835

https://thunderbird-webextensions.readthedocs.io/en/68/cloudFile.html#onfileupload-account-fileinfo

Workaround to avoid HTML attachment and for being able to edit the text:
1. copy created link
2. delete html attachment (which will remove the created link)
3. paste link back into the email