Need help! Hoping someone's able to help this old repair tech!

Ok so I'm a certified electronics repair engineer and have worked for Geek Squad repair tech team for 5 years fixing the hardware itself and I worked 1 year for Ubreakifix, 25 years self taught tech repair so im well versed at this point, but....this Apple Watch series 3 I am blindly having problems. I have an apple watch series 5 that had a lock screen when I got it and I managed to do a day 1 factory restore and it works fine.... so anyway the series 3 watch I have , had im assuming a critical software update it was in the middle of and I figure that it failed at some point, so the issue im having now is once the watch is on the charge and the watch turns on it gets stuck in the apple boot screen and just stays there till I keep the watch off the charger and let it die... I've tried the reset option of holding the power button and digital crown down till its supposed to reboot and that's supposed to factory reset it???? IDK apple watches are kinda new to me so can anyone give me some advice a list of things to try??? Like can I use my mag charger to connect it to my PC'S iTunes and reset it there?? I really need some help and I'm a tech of over 25 years but even a great Repair Tech needs a Lil help sometimes lol