The above is key. Your ABP uplinks should be received just fine, just like the OTAA Join Request was received. Next, as apparently TTN discards the ABP uplinks, for ABP indeed the following applies:
So, temporarily disable the security. And check and re-check the DevAddr, AppSKey and NwkSKey in the ABP configuration in your device. I don’t know how you need to enter those details in the FiPy’s code (Hex, lsb or msb?), but as the secrets are easily changed anyway, please post a screenshot of TTN Console while in the ABP Settings page (everything below “Activation Method”, with the keys at least partially visible), and post the code that sets those 3 values, so others can validate.
Please post code as text, not as images.
So, while I agree that access to the gateway’s log would be great: if you don’t have such access then surely you should be able to get ABP working, as by seeing that OTAA Activation you know the device is in range of at least one gateway. And for OTAA: as the application’s Data page showed that Activation, you can be quite sure that TTN has commanded a gateway to send the Join Accept downlink. Seeing the gateway’s Traffic page in TTN Console won’t help much; you would need to peek into the actual gateway’s low level logs for more details. But that would assume the gateway is failing, while probably your device is at fault.
In fact, I’d revert to your first OTAA tests and take the device outside, hold it high, and move to a place where reception of the downlink might be better.