Lost screw. Impossible to get screw spec

I have a 1st generation ring doorbell, true it’s old and has been discontinued but it is and always has, worked fine. Now, after re-charging the batts, I’ve dropped one of the screws that holds the front cover in place. I feel as though I’ve journeyed around the entire words trying to find anybody from Ring who will tell me categorically, the exact replacement spec (sending one would be even better!). A T15 torx, I’m told but when I read deeper into ordering info, it seems that 2nd, 3rd gen doorbells have slightly shorter screws. Slightly shorter? Shorter than what? And which length do I need? There is just no further info. And to add to this, Ring are adamant that the correct screw must be used to avoid battery damage but ALL their replacement kits are permanently out of stock. Various Amazon reviews say some generic screws fit - but not quite. Is this stonewalling from Ring just a ploy to get me to buy a new doorbell for the sake of a tiny screw, an extra one of which, I feel sure could have been provided in the first place. I have been considering buying more Ring security devices but in the light of this tiresome, time-wasting search, with answers that only match the unspecific online stuff anyway, I’m having 2nd thoughts. Does anybody know if Ring 1st gen replacement screw requirements differs# from models that followed it? I would be soooooo grateful. I’m in the UK.