Samsung Galaxy A5(2016) SM-A510F : "There’s an internal problem with your device. Contact your manufacturer for details" at boot

Indeed, everything you report fits with the bug. Any recovery built on the “bugged” build is reported to fail too - it does not work for me on Samsung A3!

The /e/ recovery, while developed to be optional with /e/ is not required. OTA updates work fine with my TWRP. You should be offered an update to e-0.19 before long, I do not have the recovery update ticked. I hope you can now get on with enjoying the /e/ experience.

The failure to login seems to be experienced by many new users! My recommended solution will work.