Unable to add people to Find My app

Wonder if anyone can help me with this issue.

I have been using the Find My app for many years and as of recent when I swapped over to the 15 plus, all of a sudden I am unable to view one specific contact on my app. They appeared on the people tab but not under devices. (side note: the app was working fine until today. I had been using the phone for a month without any issues until now)

Here are the things Ive done (actions I did over my devices):

-Turned off my location on the app

-Toggled off Find my iPhone

-Reset Iphone

-Toggled on Find my iPhone and Send last location/my network

-Toggled on Share my location under the Find my page in Settings

-Toggled on My Location on app

Once I did that, I went back on the Find my app and tried to add back that contact but it seems that the invitation does not go through. So I went and checked their settings on their iPhone and it seems that they are still able to view my devices under their devices tab (note they are listed as offline). However when I go to their people tab, my invite does not appear.

To be sure, I went through their settings and saw that they have toggled on to share their location under the Apple ID page within the Family sharing section. I also checked the section Find My under their Apple ID page and can confirm that I was listed under their Family section which shows that they have shared their location to me. Additionally, their phone is up to date with the software and the app. I have also tried the same steps that were listed above on their phone but had the same result.

I would also like to note that when I send the invite, it shows up with my iCloud email even though it is connected to my phone number. So it's not understanding that it's the same contact with my phone number. I made sure that my phone number is connected to the Apple ID.

Lastly, when I toggled everything back on through my phone, the option to enable the sharing location with that specific contact will try load but cancels out at the end. So the option appears greyed out. No matter what page I use to share my location i.e the section under the Apple ID Page, the option will load but not process. So the button keeps turning off. I have checked the Community pages for this issue and tried those steps but had no luck.