Recollect includes tools to keep your tags consistent and tidy.
Setting a tag style
Click the gear icon and select Settings, then open the Notes tab. Under Tags, choose how tags are capitalized: Ad hoc (however you type them), PascalCase, lowercase, or UPPERCASE.
Cleaning up tags
If you choose a tag style, click Cleanup Tags to apply it to your existing tags. To tidy your list further, click Remove Unused Tags to delete tags that are not attached to any note. To rename tags or change their colors, see tag management.
Source: https://support.recollect.fyi/preferences/how-to-clean-up-your-tags/