It's hard to find a good provider that offers reliable, good quality HD content. 4K is like a needle in a haystack.
You have to sacrifice a few things with IPTV. If you really need 4k you can always sign up with your local cable company and pay $100-$200 every month instead of $10-$20.
Also as I mentioned, 4k content is extremely limited. Nothing is really being filmed in 4k so you cant expect to get 4k for everything.
I agree with dizzurp, your best bet for 4k is movies (Kodi)or youtube or as he stated, through your local cable company.
Streaming 4k is difficult for most iptv providers other than cable companies due to bandwith etc...
Heck HD is hard enough for many iptv providers
I gather darkness to please me...