Good day.
To get a good puddle, you are on the right track.
-
For Albedo,just darken it for puddle.
lerp between original albedo texture,
and the same texture, multiplied by
something like 0.5 based on your
vertex color -
For Roughness, reduce it for puddle.
Lerp it between original roughness
and 0.01 based on your vertex color -
For Metallic, leave it at zero.
-
For Specular, either increase it for
puddle, or leave it untouched. -
For Normal, flatten it. Lerp between
original normal and (0,0,1) based on
your vertex color
You are mostly doing it all already, but the key part is probably darkening albedo instead of tinting it blue.
Finally, linking you best guide for PBR wet surfaces.
Please, upvote my answer and mark the question as resolved, if that fully covers your issue.