That's only one-fourth of the magazine?
Three of those five series are brand new. It would be strange to say that it's "losing its steam" whenever the best series are the newest ones. If anything that means it's picking up.
It's definitely weaker than before the Mass Extinction (act-age, Chainsaw Man, Demon Slayer, Food Wars!, Haikyu!!, Hinomaru Sumo, The Promised Neverland, We Never Learn, Yuuna).
But that doesn't necessarily mean that Jump has been losing its quality. The difference is that those series were all 2-4+ years old when they ended. Right now, the only series with more than two years of publication are One Piece, MHA, Dr. Stone, Black Clover, and JJK. You're comparing the quality of series with 200+ chapters to series with around 50.
It's hard to rebuild a magazine in a year. A good portion of the roster (Yozakura, UU, AyaTri, Magu, Roboco, HSF) are series probably wouldn't have survived when the magazine was more competitive. In a sense, you could consider them "placeholder series" that exist until bona fide hits emerge to replace them. If you think "the average series isn't as good anymore", it's because WSJ isn't only full of "successes" like it was in 2020. It has to build that up again.
Still, we have Mashle and TES as pretty stable successes, and WW, Sakamoto Days, and BB, which all have the potential for bright futures (and I think 4/5 of these are way above average). And the year isn't even over yet.
Which is why I don't think Jump is "losing its steam". I think it's still going full-force, it just doesn't have a lot of cushions to fall back on, since it lost most of its veterans. If you step away for two years and come back once it has developed a fair number of hits, I think you'll see a magazine that's on par with the way it was in previous years. We're just in a transitional period.
