Hey Jörg,
Sorry for the late reply, if I understand correctly the IDs are working as anchors but that it is creating #tab-id-1 variants. The add_theme_support('avia_template_builder_custom_tab_toogle_id'); is meant you give you an ID field at the bottom of the element for you to edit and use any ID that you wish, the variants are just the auto IDs that the theme would have made anyways, feel free to edit.
Please note that for an anchor link like /#fun you would enter fun in the field, no hashes.
There is also an option at Enfold Theme Options > Layout Builder > Builder Options For Developers > ID attribute input field
If your IDs are not working at all, please try removing the theme support function and use this option in the theme settings.
Best regards,
Mike