We don't see the Nitrokey 3 as being in beta. There is a stable firmware next to a test firmware released regularly. The latter can be considered "beta" or as "test" as the name suggests. Especially the FIDO2 and OpenPGPCard functionality is very mature. I'll take with me that for you a pdf seem to increase the maturity of a product and see if we can also provide one as we do for the other Nitrokeys.