You didn’t mention a single argument for why you would need a reproducible system. It sounds more like the buzz around immutable systems makes you think you are losing out on something, which is not the truth.
Maybe windows rules will now work properly instead of being buggy and delete themselves…fingers crossed Imho KDE is too big, there are so many cogwheels they miss the opportunity to actually polish each and every aspect.
What? Strg + Mousewheel, you can even set the option to only zoom text. At least on firefox. No clue what kind of browser you are using which is not capable of that.