All I can say is if you want to finesse your node idea to change the look in Resolve to match a media player on your particular monitor, graphics card, GPU driver and OS then just put that node on the timeline not per clip as a node inside other grades which is then a pain to toggle off to output your final.
The reason the rest of us use a Decklink card with an external monitor is that creating a reliable reference is at the heart of grading. You are trying to work around a problem that will chase you every time you change something like the GPU driver or a WIN update or….
My Decklink card & external monitor have survived numerous OS and Resolve version upgrades without needing to be tweaked or compensated for for many years. The cost of doing it properly against wasting of my time is absolutely an easy one to calculate.