I'm currently using Plugables's dual 4K monitor docking station (UD-6950Z).
I got it earlier this year for $140(US) and it supports two 28" 4k monitors fine. I just code so I don't really know the response for games although 4K videos run fine.
The only complaint that I have (not big) is that it doesn't have a PD USB-C port so I have to plug in both the power cord AND dock station into the laptop.
Checkout out DisplayLinks Products
search page for options that would suit you. (The link is set for dual 4K monitors)