I'm still digging through things (even with the bad internet) about some things, and sometimes I find things about scale.
Like, I find it funny how Canon increasingly wants to demonstrate Vader's power (in scale) through statements, but like, the feats don't stay the same?
In Skywalker: A Family At War, we have some statements by Anakin about having superior Force strength in the Jedi Order, about having become stronger in the Force than the Jedi who restrained him (probably referring to the Council?). We also have in Secrets of the Sith, with Sidius saying that Anakin was almost as strong as him.
But then we have Anakin being equal to Obi-Wan in the Force even on Mustafar (a place that is a nexus of the dark side), remembering that in canon there doesn't seem to be any such thing as him becoming weaker on Mustafar. Like, based on the statements, his transformation into a Sith amplified by emotions plus being on Mustafar should make him far superior in the Force than Obi-Wan.
So like Vader, it's said in Lords of Sith it's said "His injuries had deformed his body, left it broken, but they'd perfected his spirit, strengthening his connection to the Force. Suffering had birthed insight. (p11)", and then we have him getting stronger and stronger in the Force (with no statement of loss of potential, as far as I remember, except for that interview with Lucas in 2005 that I don't even know if we consider as something primary). Like, he should have far surpassed Sidious in time.
When Vader entered the Force's mental plane on Mustafar, we got a glimpse of what he would be like at his "peak," defeating all the strongest Jedi in existence and easily defeating Sidious with a red Force lightning (the same color as the Son).
But like, besides the Force lightning, what exactly is stopping Vader from being so strong in the Force? I haven't read all the comics and novels, so I'm just talking about what I've seen so far. I want to bring up something.