Roon is able to play whatever your dac is capable of receiving / decoding. If you have a DSD256 file and your dac is able to take it Roon will pass it on. Roon is not the limiter. You dac and what it is able to process (or how it it is configured in Roon) would be the limiter. All I was meaning with DSD64 in my post is that a standard sacd rip is DSD64.
As I mentioned, my dac can handle up to DSD256 so if I play a sacd rip with no upsampling it will play at DSD64. If I have a DSD256 download it’ll play at DSD256. If I have a DSD 512 download it will downsample to DSD256 as that is the highest bit rate my dac is set up to use in Roon.
If you click on advanced under you dac setup in Roon, all of those configs for max PCM and DSD sampling rates should be there. That is what is limiting things and those settings should align with your dac’s capabilities.
Hope that helps… or at least clarifies my last post. Best of luck.