Phonak Audeo L90-R Aids not showing text alerts on iPhone or hearing aids

Re: "Non-Mfi Hearing aid notifications : Phonak Audeo L90-R aids; they aren’t mfi."

You are quite right: Eg: There are no Phonak brand Hearing Aids at all, listed in Apple Support's article (link provided):List of Made for iPhone hearing devices - Apple Support

Re: "Have tried all settings possible and still can’t get audible text notifications, either on iPhone or hearing aids. The expert answers here refer to mfi aids. Anybody figured that out?"

Seems the Hearing-Aids would need to rely on Bluetooth, preferably using the newest iOS version on iPhone,

and, for the hearing-aids, up-to-date firmware, and possibly an app from the manufacturer or your hearing-professional.

Else: If you have a manual for the hearing-aids, that may provide advice on how to keep the firmware up-to-date, and whether or not an app is available for control of the hearing-aids. Another source for this information could be the manufacturers support website. Eg: https://www.phonak.com/en-us/support-options

You might want to try seeing if having Siri announce notifications can work for you:

See how to: Announce calls, messages, and more with Siri on iPhone - Apple Support

Eg: says:

Have Siri announce calls

With Announce Calls, Siri identifies incoming phone calls and FaceTime calls, which you can accept or decline using your voice.

1. Go to Settings  > Siri (or Apple Intelligence & Siri) > Announce Calls, then choose an option.
2. When a call comes in, Siri identifies the caller, and asks if you want to answer the call.

Say “yes” to accept the call or “no” to decline it.

Thank you kindly for your reply. All the best!