I know things have changed since I last did an RGH setup, which is probably where the confusion comes from; things are changing even though the scene was most active 10+ years ago.

I imagine you don’t need a NAND flasher now that ABadAvatar exists, but I could be mistaken. The process used to be, at a really high level: solder the NAND flasher/dumper, dump the original NAND, solder the RGH timer, then flash a NAND with a good timing profile for that console.

If you want a mod that persists, you’d need to do a hardware modification called the RGH exploit. It’s doable on an Xbox 360 S, but you need decent re-soldering skills to pull it off. I haven’t done it in years, but it sounds like ABadAvatar could make the process a lot easier than it used to be.