Displays Apple logo for a second then back to black.

I've got some long history with this watch and need some help from the gurus here.

History: Two or three years ago, my son was given this watch; the screen was coming off and wouldn't stay in place. I ordered a new battery and force touch sensor for it and replaced the swollen battery, sealed it back up after verifying it was working, and sent it back to him. He must have used it for a year or so, then decided to upgrade, whereupon it went into a box where it sat for another year or possibly longer.

He eventually asked if I wanted it, and I said sure, I'll take it. Once it arrived, I ordered a charger and tried to bring it up. I got the red exclamation mark in a circle with the text "support.apple.com/watch/restore" underneath it in white.

Okay, I'm thinking probably a dead battery by now, given how long it's been sitting, so I ordered one from iFixit. Put it in and tried to charge it; after that it would show the Apple logo for a second then shut back off. I tried every internet solution there was out there for button presses, reseating the battery connector, hard reset, three presses on the crown, etc. Finally went to try the last one which was to let the battery die. Took a two or three weeks as I recall, but it finally did.

Back on the charger again, eventually started showing the red snake, which turned green when it was on the charger, but from there it was stuck. The snake would never go away; I could sometimes get the apple logo for a second with a hard reset (both buttons held down) but it would go right back to the snake afterwards. Spent another couple of months fiddling with it again, but never could get it to do anything else.

Finally requested a replacement battery from iFixit, which they shipped out promptly. With the new battery, I was back to the apple logo again, at least. Once more went through all the internet solutions, but no change. Let it die again, which took something like another two or three weeks, but eventually it started showing the red snake and finally wouldn't turn on.

Back on the charger again, and in a while it showed the green snake while on the charger, then red when off, but it seemed to continue to charge, as the snake went away and now it's back to the one second Apple logo and back off again.

So that's where I'm currently stuck at. If it was an iPhone, iPad or iPod, I'd do a restore, but with the watch not having been paired to a device, there's no way to connect to it to do a restore.

I'm out of ideas, so I'm hoping the iFixit community can help me out. I've been looking at the possibility of an iBus S1 programming cable, but honestly the $70 or $80 it's going to cost me is putting me off, especially when I get buy a working watch for less than that; there's one on eBay right now in good condition with charger and extra watch bands for $59.

I admit I just don't want to accept defeat, but I'm having a hard time with the idea of buying a tool that costs more than the watch is worth.

What do you guys think, any ideas for me?