[gotham_x]

Then , I did some tests with the two rules that you gave me , this is what I'm automating :

<rule filename=".*HDR10.*|.*HDR.*|.*hdr.*" player="KMPlayer"/> KMPlayer , external player default , with contents UHD HDR = OK.
<rule videoresolution="480|576|720" player="MPC-HC"/> MPC-HC , external player default , with contents SD 480p and 576p = OK.  I have not tried with video resolution 720p , but I think it's fine.
<rule videoresolution="1080" player="MPC-BE"/> MPC-BE , external player default , with contents 2D 1080p = OK.
<rule filename=".*HEVC.*" player="PotPlayer"/> PotPlayer , external player , unfortunately I can not to have external player PotPlayer automated of default for HEVC , it is automated such as external player MPC-BE

All my contents HEVC , they are at a video resolution 1080p and they do not have HEVC in the file name , anyway , with the rule <rule filename=".*HEVC.*" player="PotPlayer"/> before this change , external player PotPlayer was automated for HEVC , though HEVC it was not in the file name. Then , at the end there is conflict with  external player PotPlayer and MPC-BE.

PS. The Video renderer is madVR. and "Rule OK." it means that the string of the rule regarding for what concerns external Player in use all right before the change.