An rpg should make feel progressions \exploration meaningful, making the game casual friendly even when the user chose max difficulty is a fundamental design flaw.Indeed, i put tons of mods to make the game feel harder. Its a problem i also had with The Witcher 3.
As a matter of fact, i think this is a deliberate design choice by CDPR to make their games casual friendly, because some of the mods i used said the game is actually putting limiters in place that make enemies and bosses easier. Enemies don't shoot guns as frequently as they technically can for example, and Adam Smasher also isn't as ruthless as he can be in the final boss fight.
They should unlock that stuff you speak about at least for max difficulty, let the player chose what type of experience he wants.