In case anyone is looking for a desktop app to replace Authy, the authy-migration tool from token2 supports exporting TOTP seeds in WinAuth compatible format (use .wa.txt for export file name). Then in WinAuth (https://winauth.github.io/winauth/index.html) , just import that file.
I have a rooted Android phone and with a simple su and cp I copied the Authy XML to another folder which you can import into the app Aegis directly (from there you can export further if you don't like Aegis). I'm currently looking at Ente Auth because it's end2end encrypted and also provides a web UI for viewing the codes. Or I use another Keepass file.
I used this and it worked very well. Not perfectly.
Because Authy doesn't have icons for a lot of services, I stored info as twitter:username, google:username, etc. The script dropped about the service name on about 10 of those, just showing the username.
I "imported" the list of QR codes into 2FAS by using my iPhone's camera. Where there wasn't a service, it would say "Service 1", "Service 2", etc.
I then went back through with 2FAS on one device and Authy on another, matching the "Service 1" to "Bubble", for example, because the TOTP codes were the same.
The one service that didn't seem to transfer was Facebook, which I have in Authy but didn't show up in the QR code list.
Several codes in Authy were duplicates, meaning that service:username was the same. 2FAS asked if I wanted to overwrite them. #1, I don't think Authy should allow the same string more than once and #2, again, a simple alphabetization would make maintaining and using Authy more agreeable.
Actually, it looks like Authy will show "twitter:username" in the compact list but doesn't show that (just "username") on the icon view unless I'd manually added them. So it wasn't stripping service names, I hadn't added them.
Still puzzled about why Facebook wasn't transferred.
I have found Authy to be reliable and I like having the TOTP codes on multiple devices. I have a powered-off iPhone at a friend's as one way to access my codes. I don't like the apathy that Twilio has shown it and I don't like the inability to export.