Some packs like ER3D or any pack that simply even uses core shaders will disable ImmediatelyFast's optimiziations, this is very harmful for modpacks when you have to tell every single pack creator to add a line to force ImmediatelyFast optimizations on the mcmeta specially for packs that are not updated for 1.20.1 or won't receive any further updates or for devs who is not willing to properly maintain their stuff or fix incompatibilities because they don't use mods.

If there was a config value to disable these checks which was false by default it would be really helpful for us modpack developers and make life much much MUCH easier.

This already exists. You can set experimental_disable_resource_pack_conflict_handling to true to disable the core shader checks globally