Unable to pair my hearing aids

What model hearing aids are you referring to? Many hearing aids are not paired through Bluetooth, but through Accessibility. Check the paperwork with your hearing aids, or consult with your audiologist. If you cannot contact them, then look for an online User Guide for your brand/model of hearing aid. You may need to pair them through the app.

I understand that, however how you pair the device is something you have to know to determine how to pair them. Did you look in Settings>Accessibility>Hearing devices? I also asked what model hearing aids you use. That matters how you would pair them as well. If you cannot answer those questions, I cannot help. If you need help, you are going to have to contact your audiologist, or the help section of the app you say you have for the hearing aid. It could very well have instructions on how to pair the devices as well.

I am using Resound Lynx, and they are connected perfectly to my iPhone 11 Pro. I also use the Resound app. Those hearing aids connect via Accessibility as I indicated in my post. I've tried to help you, but I've needed more information. I want to know what kind of hearing aids you have so that I can also do a little research, but after asking you twice, you have refused to provide that information. If you believe this to be an iOS problem, I'm afraid you may find you are mistaken, and waiting for an update is just going to result in your not being able to use your hearing aids for phone calls.

My hearing aids are Costco v. 8 and they connect easily with Smart Access App via bluetooth - iOS 13.1.3.