This answer may be too utilitarian but if you're on Windows .... I use ctrl-win-c constantly to go in and out of the b&w filter. Really helps visibility across apps.

I completely understand what you're going through since I went through the same thing before going totally blind, except that instead of waiting to be fired due to being a burden to the company and my coworkers I quit by myself. At the time that was the most sensible option since I was really unprepared to work with this condition as it took me 5 years to resume writing code.. Even a year after I resumed writing code I don't feel employable yet. I do manage to impress others and even myself with the things I can do but I don't fool myself thinking that I'd be able to adapt to a job setting where I'd have to work with others in less than ideal conditions. It's possible that one day I might feel comfortable having a job again, but this will require a lot more experience working on personal projects and collaborating with others online to push my own limits before growing enough confidence in my ability to carry my own weight.

Honestly, I recommend taking some dedicated time to learn blindness related skills, whether it be screen readers, contrast increases, or magnification. Powering through is not sustainable and learning this stuff earlier if there's progresion is alway the right call. You may even need to take some time off or blow all your vacation on a retrain. Don't take your cues from your coworkers who aren't dealing with these problems, you will need to be dynamic and make a change. I am 20/800 and do technology work running a research computing program doing admin, teaching, Zoom meetings, and programming, the works, if you have the right setup and skills even being totally blind isn't an issue for most tasks, but it can be hard to get there and you have to accept what's happening to you.

Same. I’m an administrative assistant and just today was spending a minute trying to find the pop up “are you sure you want to do this” window to close out something.

this is fairly normal. Many people “grieve” the loss of their vision like a dying family member. If you had a dying family member in the hospital, you’d be affected mentally too. It’s the same thing, and is a very common response. Perhaps talk about consouling options for the short term to help you learn how to cope with these feelings long term. It may take from a few months to a full year to come to acceptance, but with support you can make it through