mat-i-

I had the same issue as OP - bought a new Yuasa last year only for it to discharge fully after a month of neglect.
I've since bought a Noco Genius 5, which claims to repair damaged batteries. I did the first regen last night - it took 4 hours, lets see if it works!

The King

So it's probably true that a fully discharged battery will not be quite as healthy as a new one, I used the same Ctek maintainer for many years to revive countless new cars sitting on the lot. Tried to be proactive and rotate the maintainer through the ones that sat on the lot the longest, before they were completely discharged. Sometimes they were completely dead however. There were very few that didn't come back up using my trusty Ctek. Some dealerships with hundreds of new cars in stock (not so many sitting around on lots since covid) would just jump start the dead vehicle, hook it up to a quick charger for a half hour, and send it out the door. The batteries in cars that sat for weeks dead were surely compromised.

Car Analogy

Easy dealership fix, solar charger sitting on dashboard. An investment, but can keeping reusing over and over.

MikeekiM

OK... So just to close the loop on this story... I tried to use my Battery Tender to revive my battery, but it wouldn't kick into gear (because as @Car Analogy mentioned, I needed to trigger the charging mechanism with something like the 9V harness that he suggested)...

Given all of the feedback that a "once depleted" battery will like have suffered some irreparable damage, and will never be as effective as a new one... I decided to just go and take my battery back to Costco as a warranty return and grabbed a new one...

Now I need to investigate why my Battery Tender blew its fuse... I have two Battery Tenders, so for now, I am going to swap it over to the one that hasn't blown a fuse...

Thanks all!