EVGA claims up to 4133 mhz on their QVL with a specific kit but some people have reported issues.  G.Skill's QVL only goes up to 3600 mhz and imho it's pretty likely they tested faster kits but they didn't pass their tests.  Your safest bet is a kit that appears on both QVL's.
 
https://www.gskill.com/configurator?page=1&cls=1529635169&adSearch2=Tested_Speed%C2%A73600MHz,&manufacturer=1524715213&chipset=1539226140&model=1539226162
 
Granted if you really know what you're doing it's possible to tune something with good results vs. XMP, but ymmv.
 
The FTW supposedly has a daisy chain memory topology but the g.skill QVL reads more like a T-topology board in it's lack of faster 2x8 kits vs. 4x8 kits.  But in theory the daisy chain should support 2x8 really well.
 
As a side note, some of the the best high speed memory support on an available reasonable priced Z390 MB is the MSI Z390M Gaming Edge AC, which goes up to 4266CL19 2x8gb and 4000CL19 2x16gb QVL.  Buildzoid/AHOC has done extensive testing on the Z390I version with really good results and it cpu overclocks well too.  That z390m board with a 9700K and a 2080S FTW3 Ultra would be a top choice if I was building from scratch today.  I've got the normal Z390 Edge AC and recently upgraded to 4000CL19 2x16 b-die, fastest 32gb on QVL, runs well.
 
OTOH, Asus has T-topology and really good 4x8gb support on most of their Z390 boards, mostly 4266 4x8 and 4133 2x8.  Pretty much the fastest XMP 32gb you can get, on their cheaper boards too.
 
Rule of thumb with memory on Intel, it seems like low latency is more important for workstation/productivity apps while higher clocks / bandwidth is more important for max gaming FPS assuming you're not GPU limited. 
 
In the end, I'd say to get a 3600CL16 4x8gb kit that appears on the G.Skill QVL and call it good.  Those kits don't appear on the EVGA QVL, but yolo.
 
EDIT: The b-die kits, see below.