I don't mean to go OT and I don't mean to be rude - also I have not seen your scans, but I somehow doubt that your mirrorless camera scans are fine. These are severely underexposed and overdeveloped negatives, which will represent a sub-optimal starting point for your scanning for a variety of reasons. I do a lot of negative scanning and I have never been able to produce a better scan than one obtained from a well exposed and well developed medium contrast (gamma .5-.6) negative with minimal post-scanning manipulation. Conversely, I have never seen a great scan from sub-par starting material. Overly post-processed/rescued images from underexposed/overdeveloped negs are easy to spot for the trained eye. Unless of course that chalky+grainy look is what one is after.
As an aside, I have a Yashicamat 124G too, the reflective meter's utility depends on a) camera condition and b) simplicity of the light in the scene. When metering such high contrast forest scenes I'd always ignore the in-camera meter and whip out my Sekonic incident. Brick wall in pretty flat light? I might rely on the Yashicamat meter.