Text messages imported from Android phone are a mixture of test messaged and email, and maybe slack

I'm a new apple user migrating from Android. Samsung A53 5G to iPhone 15. I ran the application to import messages as part of the commissioning process of the iPhone. Now in my iPhone 15's Messages application the history is a total mess. Some message threads are a mixture of old texts and unrelated email threads. I think there are some Slack threads mixed in as well. So, the import is completely unusable. Some test threads that were to a small group now show 20 or 30 members. Messages in a given thread are a mixture of unrelated messaged from email threads, slack threads, and text messages.

-Is this a known issue?

-Do I just give up on importing android message data, reset the iPhone and start over?

-Is is safe to import anything, like my contacts?

So many questions. :-) Thanks for any help.