Decoupling Film Simulations from Primary Camera Settings?

I've been going through the same scenario because I like the custom JPG recipes- even if/when I shoot RAW as well.

I'm not sure if it's possible on the X-S10, but what I have found as a sort of work around on the X-H2 is the following (picture parameter being color/highlight/sharpness/film sim. etc, and shooting parameter being the drive mode/focus mode/etc).

I've set up the C1-C7 to my preferred custom jpg picture parameter(highlight, shadow, film sim) to start. Basically a reverse of the shooting parameters they were intended to start with.

The base shooting parameter I start with for each custom mode is currently in aperture mode (with other tweaks). I'm experimenting with the Auto Update Custom Setting function. I haven't determined yet if I prefer the camera keep any changes I make (to either the picture or shooting parameter) each time I use it, or reset to the base set up I started with when I first programed each C1-7 mode.

However, what is working so far is the way I have part of the Q button menu assigned. When I press it, I assigned the first top left menu choice to allow me to quickly rotate with the command dial and select P/A/S/M within each of those 7 Custom settings. As an example- I pick Kodak 64 in C5, and then hit Q and rotate into P/A/S/M as I want. Adjust from there and decide if I want the camera to memorize those changes (as noted in the paragraph above).

Generally, if I know I'm going to be in a mixed environment I will go with aperture or shutter priority.

It doesn't feel as fast as the X-T4 where I would first choose the shooting parameters via the dials, and then choose one my my 7 custom jpg settings from a button push (I had the back command dial mapped that pushing it allowed me to rotate through my 7 picture recipes/parameters). The X-H2 feels a bit of an inside out implementation compared to the X-T4 this way.

I haven't run across a situation where I need to adjust the shooting parameters within one of my C1-7 custom picture parameters so quickly that I lose out on a photo. I'm sure that will happen at some point, and I'll have to rethink/adjust this. Although I do find that with the numbers of buttons, adjusting most of the basic shooting parameters on the fly isn't too difficult so far.

I do miss the ability to directly adjust those shooting parameters on the X-T4 via dials. Some of the button pushing on the X-H2 seems like extra steps- especially the discussed ISO implementation (or lack of ability to more directly map that to a front or rear command dial on X-H2).

It would be brilliant if Fuji could implement a photo parameter to go with the custom shooting settings. Imagine picking a C slot for shooting parameters and then assigning a separate button to choose photo parameters (Call it PP). Mix and match a C mode with a PP mode. I think there have been a few other threads about this as well.

All this is very much in 'edit' mode and subject to change- but so far it appears to be working. I don't pretend to believe this is the best or preferred method. Indeed, I'm curious what others have to say or suggest. The forum is a good place for idea exchanges.