A screenshot showing the regular expression in the toot's main text entered into the regex101 website, with a few lines of test text which includes chord names such as "C#maj7/Gb" and "Abmadd11/D#", which the regex is duly detecting.
https://assets.growers.social/media_attachments/files/111/790/468/941/949/330/original/de881f8ff762346a.png