Custom Resolution Utility (CRU)

[Dreamic]

Hey @ToastyX, been trying to achieve certain refresh rates for a couple hours now and have no idea what is stopping me, thought you might have some insight?
Firstly this firmware finally came out for MSI 271QRX:
   

So DSC can be toggled off now, and it has a full fledged 48gbps HDMI 2.1 port, along with a certified cable it comes with.
Now there are calculators such as the LTT one and this:
https://tomverbeure.github.io/video_timings_calculator

Which show with custom timings 360Hz 2560x1440 10bit should be possible without DSC:
   
Etc.

However no matter what I do I'm unable to get 350Hz or anything higher stable, I can get 350Hz to show up in NVCP but applying it results in a mess.
Now what's extra weird is this extends to 8bit, which according to those calculators can have enough bandwidth for 460Hz at 2560x1440 (not that I expect the panel to do that), so surely it isn't a bandwidth limitation. It also hits a wall at around 345Hz just like 10bit, not being able to do 350Hz or higher when it should easily be able to do the 360Hz or at least more than 10bit can if it was a bandwidth limitation.
So what is going on? What's limiting me?

This is what I'm currently running:
   

I tried digging around CRU to see if there was some limit I could delete/override that was stopping both 10bit and 8bit at 350Hz, but no luck. Also 350Hz seems to only like to appear once you're just under 1340Mhz pixel clock, not that it's stable.
Hblank starts falling apart around 100, I don't really have more room/stability to save on pixel clock much anywhere.

Any idea what the limitation is? When 8bit 2560x1440 is hitting a wall at the same place as 10bit 2560x1440 when if it was a bandwidth limitation 8bit should be able to achieve some degree higher refresh rate but it's stopped by something at the same place. I even disabled 10bit support in CRU and 8bit still couldn't go any higher.

Thanks
Lastly here's basically everything exposed by CRU: