How can I permanently remove spam numbers in Custom Labels?

I have dug for the last couple months trying to find a solution, and I CANNOT find it. I just recently acquired an iPhone XR, and have transferred all my information over with relative ease.

I’ve had TrueCaller and Hiya as Spam-Blocking apps for my devices for the last few months, since I CONSTANTLY receive spam calls and texts on a daily basis. They do a pretty good job blocking numbers I don’t recognize, BUT I think they’ve been using my Contacts custom labels to save over 300 blocked numbers (see snapshot of partial list below).

I've read countless, Apple community forums to find solutions. These included:

• Using WhatsApp to delete them, but this doesn’t work anymore since 2013.
• Manually deleting each of them, but they ALL reappear when reloading a contact’s Edit function for the Custom Labels.
• Deleting these spam labels from iCloud.com via my desktop, but they DON’T show up as a label at all!
• Deleting the spam-blocking apps permanently, or removing them from iCloud backups, but yet these labels STILL there.
• There have been other solutions offered through Apple Community, but these are obsolete for being six-year-older posts. There is NOTHING current to resolve this.

I am at my wits end with why this is happening. I just want some resolution, because this seems like a weird aspect of having a smartphone. Why can’t I figure this out? Any CURRENT answers and solutions would be GREATLY appreciated, from both consumers and Apple support teams. Thank you!