Also speaking as a UK immigrant to Switzerland, Brexit hasn't changed anything and hasn't been a pain at all. If anything it's brought the UK closer to Switzerland because it's now got a friend who's also outside the UK and is big in financial services, so there have been lots of quick deals and collaborations signed between the two countries. But beyond that it makes no difference to my life.
Now it seems maybe you mis-understand the rules, which may be why you're claiming it's had a big impact on you when it should not. There are two things to recall:
1. The rights to a work permit only changed from January of this year. Everyone resident before that retains their prior rights. As you say you're soon going to apply for citizenship you presumably already have a work permit, so it's irrelevant - the grandfathering arrangement would apply for you.
2. Schengen rules say you must have ID with you at all times, even for internal travel. It's not well enforced so often people don't realize this, but you have always needed national ID like a passport not only to cross borders, but in theory, to go anywhere at all, even locally. Obviously the latter is ignored all the time but that's what the rules say. Also, the UK has never been a part of Schengen, and the UK leaving doesn't affect Schengen rules or Switzerland's application of them, so there's genuinely no change here.