I worked post diagnosis for quite a few years. I told my boss, my HR department and my team. I didn’t bother telling people I didn’t work directly with, or my clients (I did a fair amount of consultancy work).
In general my team were fabulous. I remember one day having a meeting with a client and finding walking hard that day, one of my lovely colleagues just hailed a black cab so we could get back to the office in central London without using the tube (and he paid for it too!).
There was one fellow workmate (who knew I had MS) who wanted to walk up 3 flights of stairs one day instead of using the lift. He tried telling me ‘you need to keep using your legs!’ I told him, ‘no bloody way, I’ll decide what’s best for my legs, and today it’s the lift!’
I suggest you tell the people you need to and want to. Otherwise, keep it to yourself if that makes it easier on you.
Best of luck (and welcome to the forum.)