Hi nazpastorjames,
welcome to the Apple (user-to-user) Community.
Re: Others can't hear me when audio streams to my hearing aids:
What to do: If the microphones don't work - Apple Support
Check you do not have a focus set ... Do Not Disturb.
Also: see: While on a call on iPhone - Apple Support
Eg: says:
"When you’re on a phone call:
Tap the audio button, then choose an audio destination".
and
"Adjust the audio during a call
To change the volume, press the volume buttons on the side of iPhone
(make sure "mute" is not on)"
________________________________________________________________________-
Re: "After the last iOS update, others can't hear my voice when on a phone call."
Seems you are still using your iPhone 7 with iOS11 ?
If so, you may want to update your iPhone to the newest compatible iOS version: iOS 15.8.2
Seems Apple often suggests we keep devices up-to-date for security, as well as "bug"-fixes etc.
Try going to Settings > General > Software update to check if another update is waiting to be installed.
Re: "Is there a way to set my phone to work ALWAYS with my hearing aids?"
We do not know which update you installed ...
If something is not working as expected on your iPhone, you might try re-starting it. (ie: deletes temporary files, re-established connections, may update recent setting changes, and often restores order)
If needed: How to: Restart your iPhone - Apple Support
_________________
If you still need help:
Wondering if your hearing aids are compatible with your iPhone ...
For compatibility tips you can browse: Use Made for iPhone hearing devices - Apple Support
Apple also has a long list of the compatible hearing aids. List of Made for iPhone hearing devices - Apple Support
I counted 15 different Beltone models ... you might check if yours are listed.
If so, the article contains links to various tips you may wish to use.
If your hearing aids are not "Made for iPhone" compatible, seems the Beltone routine does work, though tedious.
All the best :-)