This number is nonsense made up by czech Forbes, the actual budget was around 15-20 incl. marketing (but marketing was tiny portion of it).
KCD2 will have around two-three times bigger budget, around 50-60 mil (more than twice as many inhouse devs, inflation, bigger marketing budget).
Regarding UI, recent post about it from Dan Vávra:
If I'm happy about something, it's about this reaction of a Polish YouTuber (and not only him) to our new interface, inventory and the entire UI. Because I consider UI to be a very important thing, in all the games I've made, I'm the author of the design, often I also did its graphics. For KCD2, I wanted us to remake it completely in 3D with realtime lighting and keep the original principles from KCD1 that worked. It is inspired by wooden Gothic altars and the old town clock. And multiple people worked on it for 6 years. We really tinkered with every detail and with every pixel. The only thing we failed to implement is the 3D map. Which makes me annoyed, but we just couldn't make it in time.
After all that work, which is not always appreciated by everyone and at all stages of implementation, and when you really have to defend some decisions very hard because a lot of people on the team doubt them or even protest against them, then you are in doubt how customers will accept it. If anyone even notices that it took so much work. If it made sense to bother.
So it's quite a pleasure when someone sees it and their first impression is that they literally exclaim enthusiastically:
"OH FUCK! GOOD! THIS IS IT! THAT LOOKS BEAUTIFUL! GOOD! AND IT'S STILL BY CANDLELIGHT! THAT'S WELL DONE! THAT LOOKS COOL!"