In my experience, Authy does port your OTP tokens between devices. The ones that use their backend infrastructure are tied to your phone number, and are ported

In my experience, Authy does port your OTP tokens between devices. The ones that use their backend infrastructure are tied to your phone number, and are ported automatically. Ones that you import from other TOTP-based systems via a QR code (like Google Authenticator) are private to your device by default. But if you really want, you can turn on the optional "backup" feature in settings, which will upload them to your Authy account and automatically port them between phones. Sure, it requires an extra step... but to be fair, normal behavior for TOTP codes is to keep them 100% local to the device. I'd argue this is a reasonable default, given that security is involved. TOTP services almost always require a backup method (SMS or scratch codes) in case you switch phones, anyway.