Dear Bryan,
your statement “PL will support a dng produced by Adobe DNG converter” is only correct if the generated DNG by Adobe DNG converter includes data by a camera which is supported by DXO.
If not, you got a message that the dng file could not be developed because the camera is not supported by DXO. The same file can be opened with Affinity photo and each other software I own.
For me this is not a real DNG support.
Edit: don’t forgot to vote for Support any DNG file