Avatar says hello.
I think they can do alien worlds that look great very easily. This could be movie/show/game and there are other examples. Though it would need big budget investment to be done well and really go deep into the characters, magic, worlds, etc.
Well, with we are talking about expending infinite money then I'm sure anything is possible, I mean, just look at Guardians of Galaxy, it portrays many planets with particular environment and is mostly done using a very nice CGI and sometimes practical effects
Avatar had a 250 million production budget for a loving with around 160 minutes. And sources actually says the real budget for Avatar was closer to 1 billion because of R&D expending to develop the technology necessary to make the movie possible, and of course other expenses such as marketing, distribution, legals, etc
The only Stream show with such a huge investment is the upcoming Lord of the Rings series.