The latest version 0.21 of the Tag Groups plugin features a new shortcode that creates an accordion instead of tabs:
Chatty Mango
Features
block caching color Dynamic Post Filter filter Gutenberg Meta Box natural sorting pagination post filter random sorting spiral tag cloud Toggle Post Filter waves
Software
admin Ajax blog bugfixes caching categories comments debug documentation error export free software hack HTML junk localization performance plugin post filter redirection REST API search shortcode spam statistics sticky post tags theme update workaround wp-mail
Tools and Services
Other
The options are documented in the settings. As usual, please post any support requests on the official support forum.