For a quiet host, it’s hard to beat a P226. The Legion SAO RX is my choice for an out of the box option. Also, Barsto sells a threaded bull barrel for your P320 X5.
The DVC Tactical model was discontinued and never offered with a HOST cut, STI is offering the Tactical model with a HOST cut option. Also, suppressor height sights will not cowitness with a Deltapoint Pro according to the STI rep I’ve spoken to in the past.