I don't know about optical switches, but I know that you can still buy new ALPS alike keyboards from Mathias. I have 4 different models of them e.g. this one. There is a PC version that is branded "quiet pro" that I have been using in the office for a while, but I stopped using it when COVID came.
keyboards
Discussion on all things keyboards
This was a while ago so it's possible their quality control has improved over the years, but I had two Matias TactilePro keyboards fail: the first developed keybounce/chatter after a few months, the replacement developed it after a few weeks then had keys fail. They gave me some mild run around the second time and I just wrote it off rather than deal with them.
I have a number of other keyboards, including Unicomp, and only Matias and a Filco Majestouch gave me problems and the Filco went several years of daily use before needing a key switch to be replaced.
I tried some software compensators for doublestrikes but i found they didnt suit my needs at any point of tuning. I’m at least glad others have had similar experiences and I’m not just uniquely cursed.