Ofc they are fillers, only a few do what cowboy bebop does best (I remember one about a criminal called rico and the tangent episode about the war veteran with tits), “plot” is not the only thing happening in those vicious related ones you are talking about, and you are leaving the Ed farewell one out*, they are the ones where attempts to poesy are done along the other fillers where characters are sorta fleshed out, 'cause that’s where cowboy bebop adds some emotional impact to whatever great shot and even then it’s too bad vicious is just an evil dude- the fall from ep5 where “fragments of the past” or flashbacks are reviewed as he seems to be about to die is cool, the cinematic flock when julia gets hit, the speech about fake eye/real eye along with whatever speech adding to anything, the vhs detritus stuff from the past if that counts and whatever else adds to the characters, there isn’t nearly enough time dedicated to the final days of the bebop gang because a shit ton of “feel good” episodes must air, yes ofc it’s intended but those are also fillers to feel good just like in every other anime. It’s really watanabe going episodic and not dealing well with long arcs, terror in resonance being total shit in the league of gatchaman for all the cool ideas they both have, gatchaman being the one with most potential and at the same time being dumb as hell.
The difference with 99% of animes is that in both cowboy bebop and eva don’t have rote fillers at the beach in summer or whatever. On one hand you have stuff akin to parody or music videos, on the other you have psychological breakdowns, both with strenghts and weaknesses and in both cases way too many except eva did it because of budget restrictions.
It’s also a difference in cinematography, most animes actually drool for something like cowboy bebop and put some “feel good” music in the background or when the episode is about to end - it doesn’t really matter if the music sucks or not because it’s for effect, eva doesn’t do any of this and instead goes for rythm/ silence/ silent close ups for emotional effect, even movies go for feel good music at the end (matrix, inception, the bebop movie and whatever) without being about bebop or music videos or whatever anime trend.
*it’s not about arc-filler-arc, it’s not about vicious, it’s about the end of the bebop crew, it’s episodic and 70-80% of the eps are feel good fillers written between the good stuff