BankID will not work (at least not with Swedbank) unless the device it's on has enabled Android ID (a unique device identifier from Google). I've tested and confirmed this on a Nexus 5 running LineageOS v14.1 with microG.

I noticed that it's still possible to install the BankID app and setup a new Bankid without first registering the device with Google (i.e., without enabling Android ID), but any authentication attempts with BankID will fail. Unless Android ID is enabled, that is.

Enligt BankID:s systemkrav så krävs lägst Android 6 med Google Play Services (eller Huawei Mobile Services).

Freja eID also requires Android ID to work.

https://lists.dfri.se/listan/msg01875.html