Beagle Eating His Poop– Help!!

Hi, looking for advice.

I have an almost one year old male beagle. He has BEEN having the problem of eating his own poop (inside only. He goes poop fine outside and doesn't try to eat it).

We've tried what feels like everything. And I know the solution is to just quickly pick it up but we can't keep an eye on him 24/7.

Another thing thats new is anal gland expression, never knew this was a thing since our 3 year old beagle has never had that issue. Anyway, we went to the vet to get them expressed maybe a month ago. A couple nights ago as we're about to sleep, we smell the smell again. So we got up and expressed them ourselves.

Does anyone know if the lack of natural expression may be linked to his eating of his poop? Maybe the poop "tastes" better without the smelly fluid? idk?

Any tips for potty training a one year old pup or stopping this? We're having a hard time… This pup is such a cutie but he's so dumb.

Any help or advice would be so appreciated.