Found a thing that works awesomely for me and wanted to share.
The rundown: I have an auditory processing disorder. My ears work fine, but my brain doesn't turn what I'm hearing into anything useful a lot of the time.
I've previously tried ip-relay, which is sort of like TTY, and it worked okay for me, but not great. (All comments in this post are just about how the stuff worked for me personally. Different people prefer different things.)
I've also previously tried VRS, Video Relay Service, which is where you use ASL with an interpreter who relays between you and the hearing person. Not a great fit for me because my ASL isn't awesome to that degree yet, and it had the same issue for me as ip-relay - I couldn't speak for myself.
ANYway. The ASL tutor suggested I try VCO, Voice Carry Over. That's where I can talk directly to the person I'm calling - they can hear my voice. Then I can also hear them speaking, and at the same time an interpreter also signs to me what they're saying. So I get visual plus auditory, which is almost always the best situation for me.
It's working SPECTACULARLY for me. It's just the right fit. I've had multiple over-an-hour phone conversations with friends since I started using it, and I've also called for take out a couple of times, neither of which I've been able to do easily in several years.
Anyway, just wanted to share in case it's something someone here could use but hadn't yet considered.
I use Purple as my VRS/VCO provider, if that's useful.