You’re spot on, I no longer deal with said “veil of plausible deniability”
This is 100% how I approach all sorts of relationships in my life, not just romantic. That’s called direct and open communication.
I will straight up ask (politely) that someone clarify what their explicit stance is, if they refuse or try to play coy about it I simply let them know I don’t know where they stand and I don’t know what they want.
I’ve done this with bosses, siblings, my son, and my partner. I have grown to respect people much more because I understand them better and have also cut out some toxicity from my life that I didn’t know was eating away at my happiness.