Macbook Pro 16" Clamshell Mode Power Delivery with 2 USB-C PD Monitors
The MacBook Pro 16" will be connected via USB-C to both of them [LG 27UK850-W monitors] and use them as external monitors. Since both can charge it as well will the MacBook Pro 16" charge faster while being connected to both or will just one monitor be able to deliver the charging at a time?


The MacBook Pro will only charge from a single port at any one time.  It doesn't matter if the power is coming from a monitor with Power Delivery or from USB-C Power Adapters, it will only take charge from one.  Usually the one with the higher power rating or if identical, the first one connected.