Many intercom communicators have this issue.
HMS' Trac-Com's v2.0 has greatly reduced this feedback/interference issue compared to their v1.0 and the Chatterboxes out there. For a while HMS was offering a reduced price to upgrade to v2 from v1 - not sure if they still do but worth the ask.
https://www.hmsmotorsport.com/item/trac-com-intercom-v2/trac-com
Good luck!
