Hi minijulie
welcome to the Apple (user-to-user) Community.
Re: "Cochlear Implant and hearing aid constantly disconnecting from bluetooth since phone has been updated"
For iPhone: You might want to check: Settings > Accessibility > Hearing Devices controls
Else: Wondering if there is a firmware update (or an app / update) available for your hearing aids.
You might want to check with your hearing professional, or the manufacturer's support team on their website.
If needed: There are other trouble-shooting tips from Apple Support in the linked articles below:
Use Made for iPhone hearing devices - Apple Support
Use hearing devices with iPhone - Apple Support
Accessibility info. / support / contact options etc.
Apple's Accessibility Support Website:
(NB: You can "Get Support" from the link at the bottom of their website (link below):
Accessibility Support - Official Apple Suppor
All the best :-)