graphite-or-graphene Well it's good the server recognizes there's traffic in and out, hopefully the client is saying the same. I believe sent just means the server flung that much data at the client IP and port while received should mean they have been received and decrypted.
I would double check the client log against one from a working client line by line and see what, if anything, is different. You could also try opening and checking the .ovpn files and comparing them as well. This is often one of the easier ways to troubleshoot issues when you have working and non-working devices.
As for WireGuard, the hard part about it is really just doing key exchanges between the clients and the server. OpenVPN does make that easier by simply exporting everything you need at once from the server instead of every endpoint generating their own key pair and then you needing to copy around public keys.