If possible, using Special K’s HDR Retrofit is a much more functional, less risky option than this. That said:
Just to be sure you and anyone else who considers doing this are aware, that slider controls desktop/SDR paperwhite. 0=80 nits, and each tick on the slider adds 4 nits, so 100=480 nits. (It may be on a slight curve such that 100=500 nits in at least Win11. Reports vary.)
30 (200 nits) is on the high end for actual desktop use, and anything above that is more or less actively trying to burn your OLED, so you absolutely don’t want to crank it and leave it there.
You should also know Windows (currently) maps SDR into HDR using piecewise sRGB gamma, which will be incorrect for a great many things. If you have an 800ish nit peak brightness display, you can change this to pure power 2.2 gamma using dylanraga’s win11hdr-srgb-to-gamma2.2-icm color profile. (He also has a tutorial explaining how to generate profiles for alternate gamma levels and/or different peak brightness displays.)
(Also, last i knew, you could push the slider past 100 by editing the registry if you really wanted to, but the warning about burn risk apply even moreso at that point.)