UE4.23 will have huge improvements on performance, features still missing, and better denoiser code. Remember: realtime raytracing is in early access, meaning it is not ready yet and under intensive development. The presentations you see are from companies that not only hold their own personnel to work on their own improvements on top of what the engine had, but also some of them are working with experimental code provided by Epic which is serving as basis to have the work done for “public” release. There will be some other improvements that will go as far as releases 4.25 and probably 4.26, but you can expect the most important ones for quality arriving now at 4.23 and 4.24.