Lifting isn't just about your muscles. You need the neural skill to activate your muscles. You can strain your CNS by lifting in specific ways to require more neural activation.

Lifts that are complicated in number of muscles used mean more neural involvement in the lift. That is why deadlifts and grip, both are lots of muscles working together. Hands are way more complicated than you think with lots of tiny muscles.

Next is how you modulate strength, muscle is binary on and off. Take a 10% of your strength lift. Your body activates 10% muscle fibers to 100% output to modulate strength. It does not activate 100% of the muscle but to 10% output or anything in between. The body has its favorite fibers in each muscle group and always uses them to their limit before involving more fibers. That means the only way to activate 100% of a muscle group is to lift to failure. Since more fibers activated requires more neural output failure lifts get the most neural activation possible out of that lift.

Putting those together you get deadlifts plus grip to failure for maximum CNS stress. Your CNS then crashes and recovers over a few days coming back stronger.

I've validated this on myself with Oura data. It shows the fatigue in my hrv after a lifting day. It also shows that my daily stress time is reducing over time by lifting this way, which shows that the CNS adaptation generalized to other life stress management besides lifting.

Be warned though, you will be very tired for a day or 2 if you properly stress your CNS. Be ready to sleep more.