I'd say for Bebop, it's more akin to 30-40% plot and 60-70% filler. As far as episodes with a full ongoing plot, the only episodes that really have much in that regard are the ones with Vicious (episodes 5, 12-13 and 25-26) and those aren't really the best for an ongoing plot since he's a very bland villain. The most engaging part of the series would probably be Faye's character arc, which whilst not anything overly compelling, is still a lot more interesting of a character arc than a lot of significant female characters in anime get (especially nowadays). It does have a few themes about nihilism, but they don't get explored much and just end up going nowhere.
That's not to say it's story is bad, as Faye's arc is good and the series at least has a solid end that left no room for an unnecessary sequel, but it's not really outstanding in terms of plot.
Also, some filler episodes are just complete boring
for anything but visuals, such as an episode 11 offering absolutely nothing to either plot or characters and possibly being a dream depending how you interpret the ending or episode 20 being nothing other than Spike tracking down a psychotic clown in a theme park.
If wanting to stick to only the episodes that offer much in terms of plot/characters, the best way to watch them would be 1-6, 9-10, 12-13, 15-16, 17, 24-26, or just watch all the episodes in order if still wanting some entertainment since a few of the episodic stories are still decent (just skip episodes 11 and 20, as well as maybe 19).