My phone (Huawei P30 Pro) doesn’t have hardware AV1 decode support. However, if I take an AV1 video, transfer it to my phone and play it using the built in player, it works! There should be an option to use the CPU to decode if there is no hardware decoder.
Even if it is in the settings on the app so that people have to enable it, that would at least leave it down to the user.