LDRXN is the max pressure turbo will boost. KFMIRL is the max specified pressure engine can reach and is capped by LDRXN.
Over ~0.2bar of LDRXN values, will cause limp mode.
LDORXN is load (%) overboost protection. So if you set it to 150%, when engine reads over it (continuous or instantly over ~165%) will cut boost.

Not quite exact.
Its switched in instead of LDRXN/LDRXNZK during overboost.
From FR http://www.nefariousmotorsports.com/wiki/index.php/LDRLMX_3.100_(Calculation_of_LDR_Maximum_Cylinder_Charge_rlmax):
LDORXN is maximum cylinder charge LDR during E_ldo (overboost error)
In the overboost condition (E_ldo) an engine speed dependent limit (LDORXN) is switched in so that both the engine and the turbocharger adequately protected. Switching back also occurs only when resetting the error (E_ldo) and in idle-mode (B_ll).

None of that is correct.

LDRXN is basic max specified load. There's an additive for overboost if active, then factors for knock, IAT, oil temp, and coolant temp. These can all raise or lower max specified load rlmxko_w.

Then max PR is converted to load and limits rlmxko_w.

If there are errors in EGT sensors, IAT sensor, either CTS, or oil temp, then max pressure is converted to load and limits max specified load as well.

If lde exceeds KFDLDULS for a period of time, then max specified load is also limited to LDORXN.

Finally, there's an additive for adaptation channels (lemmi).

This final max specified load, rlmax, limits the output of KFMIRL.

search for rl_w and trace it back to pvpdks_w

Thank you both !!!