It's not the Windows updates, at least for my issue. Windows is fully updated. Nvidia drivers are fully updated. It makes no difference. I can downgrade the bedrock client to 1.17.11 and I get RTX working again, so it looks like something is broken after that in the client. I'm also getting horrible frame-rate (down to 23fps) and this is on an RTX 3090 with no texture packs (I removed the RTX ones since they aren't working anyway). Also, I have a second machine with a 2080 Super and RTX works on that in bedrock, so go figure. My 3090 box and my 2080 Super are running the same bedrock client (1.17.34 currently) and RTX works on one and not the other - both up to date with Nvidia drivers and Windows updates.
Can I just say, it's incredibly frustrating how I can't get any debug information from the client or log files about what it thinks is going on - it says the device is not supported, I would LOVE to know what it thinks the device is.
Just adding my +1. RTX 3090; AMD Ryzen Threadripper PRO 3975WX; Windows 10 Version 10.0.18363 Build 18363 fully up to date. Nvidia Game Ready Driver 472.12 (latest). Bedrock. 1.17.30
So RTX was working fine, for weeks. I've opened the game today and RTX is not enabled and can't be enabled. I hadn't changed anything. I can't re-enable it. RTX texture packs have a warning on them saying my device does not support RTX. I then updated nvidia driver to the one above. Did not make any difference. GeForce Experience 'sees' Minecraft, and will 'optimise' settings including having RTX on, but this has no effect in game. Tried uninstalling and reinstalling from MS Store - problem remains the same. I have now downgraded to 1.17.11, and RTX works again as expected - I can download e.g. the nvidia Hilltop Lifestyle demo and it all works fine.
It really looks like this has been broken on your end somewhere between 1.17.11 and 1.17.30
OK, I've fixed this on my machine. As others have mentioned, the problem (in my case) was related to Windows versions. I thought I had dismissed this as my issue, since going to Windows Update showed the machine was fully up to date. However, I realised that because I have the Enterprise version of Windows 10 it was keeping me back on a fairly old Windows 10 build (1909). So I went to downloaded the Update Assistant here: https://www.microsoft.com/en-gb/software-download/windows10 and manually updated to 21H2. That's the only thing I've changed, and everything is working again - I can download and run the nvidia RTX examples from the marketplace without issue, and the Kelly's RTX packs I was using before are all working again. I hope this helps somebody.