DLSS4 features can be forced on existing titles. I was thinking of this very issue when I came across this thread so I looked into it and found that you can override any DLSS feature with it's newer version 4 equivalent.
One nice benefit is that you can force the new transformer up-scaling model which gives a significant improvement in upscale quality.
This link shows how:
https://pcoptimizedsettings.com/enable-dlss-4-in-any-dlss-2-dlss-3-game-transformer-upscale-faster-frame-gen/
You can also replace the entire DLSS file in the program directory.
Also...
Turns out some nice people have already developed tools to make it easier:
https://github.com/beeradmoore/dlss-swapper
https://github.com/kaanaldemir/DLSS-Override-For-All-Games
One of those links shows how to force the DLSS driver overlay which tells you what features you are currently using (I think)
An aside... I had always thought that drawing after the upscaling was a default feature of DLSS. Don't quote me on that.