Lukewarm take but I think one of the biggest problems with the way kink is discussed on Tumblr and in lots of online spaces is the essentialism that often comes up when describing the role of subbing or domming. No sex act is inherently dominant or submissive, no body part is inherently associated with a particular role. There is no ideal Dom or ideal sub. It's all just how the scene is framed.
My domming ideology, my preference for how I conduct myself and the way that I view myself in Domspace is probably just as close to a brat or pleasure sub as it is to the stereotypical cis male Dom archetype that's very common in these spaces.
I'm sadistic because I enjoy the feelings I can give other people. I love the way they can react to pain, pleasure, and any combination of the two I inflict. It arouses me to have a submissive exert themselves for my pleasure. For that reason, my dominance is almost oriented around a certain degree of selfishness. I want to make you moan a certain way, cry just the way I like, whine and beg in the exact way that scratches that sadistic itch I have. It's like this inverted, perverse version of pleasure domming. It's so addictive. Even when I'm doing something which is meant to be physically pleasurable for you, I enjoy it because it gets me off too. Greedy, selfish dominance.
That same mindset extends to physical pleasure. I'm extremely fucking greedy. I love having my ass eaten and making a sub focus all their effort and energy into getting me off for as long as possible. I love being edged and overstimulated for that same reason. It's about me and my pleasure and they're just a toy I'm using to get off. I like it when they top for me and do the work because they're pushing themselves and working hard for my pleasure.
I love doing scenes where I basically use them to masterbate, or treat them like a pleasureless sex toy that can only get me off. Denial also seeps into this aspect of kink for me, where the dichotomy between my focus on my own pleasure and taking away theirs creates exciting and intense dynamics.
Am I still physically dominant? Very. Do I love doing the work and topping? Obviously. Am I sadistic and cruel for their pleasure as much as mine? All the time. But those components of dominance are expected and typical, while the selfish, self-pleasuring aspects of dominance are mostly expected from Femdoms (a group who has a ton of unearned stereotypes themselves).
My final point is that kink has no gender, sex acts have no specific level of dominance, anyone can enjoy anything and frame it however they want. Not all subs give head not all doms top.