Hey Neil,
Thanks for the response. I understand (for the most part) that video editing is notably more labor-intensive in non-linear editing systems due to the fact that a single second of video consists of 24-60 frames. What had previously eluded me, and which you've kindly clarified, is the process of achieving a similar effect in PS using adjustment layers and the brush tool but in Premiere Pro.
If I understand correctly, an adjustment layer in PR applies all its effects to the track below, unlike in PS. I can employ Lumetri to mask in the effect, but can I also adjust the blend mode to overlay using Lumetri? As far as I'm aware, blend modes are only accessible in the drop-down menu for the opacity effect.
There are other means of getting places. The Track matte effect for instance. Alt-drag a clip up twice so the same clip is on 3 tracks. On top use a mask or Lumetri HSL key to select an area or hue.
On middle clip apply track matte, setting to take input from V3 by luminance. Now any changes applied in an effect on V2 is applied limited to the selection on V3 to the clip on V1.
Everyone's mileage always varies ...