I've been in contact with the support and they've really went above and beyond considering I'm just a second hand user. Really impressed.
Anyway, for anyone else wondering or stumbling over this I'll share some answers I got:
The button posted above has the right dimensions, and is a suitable replacement.
But before you go poking around with a soldering iron:
...it's good to note that the buttons on our instruments are self cleaning and you may be able to clear up any intermittent operation by pressing a button with a great deal of force 50-100 times. If you notice the buttons behavior improves, continue to press on the button and then check whether there is further improvement.
This actually fixed 70% of the issues I was having, so now I'm down to replacing just two or three.
I'll update whenever I've replaced the malfunctioning ones (might be a while though).