Hello, my name is Fabian, I've been assigned to support your case.
I appreciate your interest in our products.
I may have to add that this feature doesn't have a specific register for decreasing the antenna distance detection. This is very attached to the antenna design and its fine-tuning. For this, I will have to recommend you to please check the Antenna Design Application Note and the Antenna Design video series.
Additional to this, there is a feature in the IC that will help you on this matter but, keep in mind that this is the last step of the antenna design. DPC allows controlling the transmitter driver voltage on the actual transmitter current. Please check section 9.11 of the PN5190 Datasheet
I may have to add that you can use NFC Cockpit for this fine-tuning, this is a tool that will help you configure your IC, in a graphical interface.
Best Regards,
Fabian