Greetings TaC26,
We'd love to assist you with My Guides. You should be able to delete them using these steps:
"Remove a guide
- Tap your picture or initials at the top right of the search card, then tap Guides.
- If neither your picture nor initials appears, tap Cancel next to the search field, or tap the search field, then tap Cancel.
- Tap Edit at the bottom of the screen.
- Select a guide, then tap Delete."
More details here: Organize places in My Guides in Maps on iPhone
If you're unable to complete this task, Maps may not be working as expected. In that case, this resource can walk you through some additional steps that may help resolve this issue: If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open
Thanks for connecting with Apple Support Communities.
All the best!