But no, I don't care for HxH
I don't know what you tried of HxH, but I read the manga and watched both the old and the new anime. They are pretty diffrent in flavour, despite having (more or less) basically the same plot. (Aside from plot progress obviously). The old anime is directed by Furuhashi (Kenshin OVAs, Gundam Origin) and it totally makes a diffrence. The Manga is also a thing of itself. It's like a big buffet with all kinds of things served, where each dish could be its own show. (Which actually happens. Liar Game and Toriko are all about things that were also there as one little adventure in HxH.) And each adaption emphasised on some sort of dish more. The old anime (sans Greed Island) has a much more mature tone, while the newer one is more child-cartoonish in style.
I'm not much of a HxH fan myself, the but old anime is worth a try just for Furihashi's directing and the manga for seeing just how it does just about another very diffrent thing with each arc. I really don't like the 2011 anime much at all, though. It lessened those parts of the buffet I appreciated in favor of exactly those I didn't particularly like.
or Jojo. What irritates me the most are the battle-type shonen like the Big 5; I just want to rip my hair out when I try to watch even a single episode of DBZ, Bleach or Naruto, with all the never-ending power-ups and/or the eternal taunting back and forth over the course of a single fight spanning 3 episodes...
Why anyone would enjoy something like that is the real mystery to me...
Wait for moment. But Naruto isn't just Naruto either. Just look at this:
(It a ton better if you know the backstory.)
Naruto the anime has tons of problems, but occasionally you get these absolutely georgeous pieces, which are pure eyecandy. There is also the whole end fight of the shows two protagonists which isn't just a sequence but a couple of shole episodes, where studio pierrot went all out and you start to wonder just how great this show would be if they had the resources to put as much effort into the whole show. (Obviously never going to happen, but I prefer a bunch of episodes totoally discardably in favor of some great ones instead of mediocre ones across the board.)
Naruto the Manga suffers a bit less than the anime, still has it's problems especially after half time and Naruto the boy is absurdly annoying, but it still has its very strong moments.
I would recommend checking out Boruto. It's about as completely diffrent to Naruto as the second LE season is to its first, but makes up for a great extention in a similiar way and it would seem to me it's slowly fixing up what Naruto every just hinted at, but never went around to properly do. What's more, Boruto is catered at two audiences at the same time, one of which are the aged Naruto fans, who mostly went to become fathers themselves by now and the newer generation of current times, which the evolved setting represently pretty nicely. Also Boruto is not even 10% as obnoxious as Naruto was as a child. And you can start without having necessarily have watched all those Naruto episodes, though it definitely increases enjoyment to understand all the backgrounds. I didn't finished Naruto when I started, I had only read half of the manga, but then I went back and read it in one go did some cherry picking on the anime's best moments.
Bleach is all about the rule of cool. The author even says so himself, he wants to draw cool stuff and everything else is somewhow shoestrung around that (and at some point went from decent to down the drain.) Jojo is also very much all about being cool, but going about it in a diffrent sort of aesthehic and technique. Seems like you either like that or you don't. (I don't like Jojo for my part.)
I think you really need to have watched Shonen stuff in general at the right age at the right time, to be hooked on it and later feast onto all the nostalgia. So if you say you are already over 50 you might have long since missed the boat for it already. (Though there are of course
Shonens who offer more.) I was watching DB, when I was some 12 years old and found it decent enough with some cool ideas. (I still think Bulma's casule gadgets are something I'd really would like to have in reality) and DBZ's beginning did appeal to me when I was reading the manga at age 13 or something. Then I didn't get around it for some years and when I looked later it wasn't interesting at all anymore and I doubt at this point there is much of a chance it ever will. Also DB and DBZ was revolutionary for its time. Nowadays you have a ton of titles one to even three generations after which took what made DB/Z special and do it their own way with sometimes more tastier flavours. (Naruto for one.) But just as is with most things, the one who came first comes around to one is the "original" and everything else later doesn't feel as fresh.
(Speaking of that, DBZ could be accused of being a rip of of Saint Seiya, too. Only that Seiya probably is only known in the west in France and Italy.)
Also, some other hammer agrument: Knowing all that shonen stuff maxes out your Gintama enjoyment, once you got into that one. (Or Bakuman.)