I recently watched both and really liked it.
A friend have been recommending me to watch Solo Leveling for a while now, and despite my fears of it just being another generic ass story and protagonist, I actually enjoyed it.
The only 2 complaints I can think of right now are that the other characters aren't really that interesting outside the protagonist, so I kinda don't care about them very much, and I think not having any commentary on the very predatory capitalism showed in the story is a bit of a let down, like, the protagonist barely makes money, there's literal monopolization of portals and creation of guilds for profit seeking, yet there's 0 commentary on that, unless I missed something.
That being said, I like the protagonist, he's not an extremely evil or perfectly good guy, he's just a dude that got dragged along and have to make some though decisions here and there.
Spoiler for the end of the season
Also, at the end of the first season the dude becomes a necromancer, and I'm a sucker for necromancy, so I'm excited to see where it goes lol.
For Trigun, I watched the old anime a while ago, and I thought this new one would go a completely different route, but I was gladly surprised with how it turned out. I just finished watching it and I really liked it. I never read the manga so I don't know how close it is to the original story, but I was shocked with how different it was from the old adaptation. I remember a lot of people complaining about Vash's new design, but honestly the only issue I have with it is that it's a bit too simple lol, I wish his clothing was more complex/overdesigned.
Spoiler about the story
The only real complain I have with the story is that it doesn't really tries to counter Knives' narrative.
Like, he's obviously right about how the plants are used and killed by humans, but he's a genocidal manipulative race supremacist that wants to create a paradise for his species with all means necessary, and the only thing to counter his narrative is Vash saying it doesn't need to be like that and that humans and plants can coexist, but never explaining how, never addressing the issue with how plants are used and discarded.
I really hope this gets tackled in the next season, because right now it makes it seems like Knives actions and way of thinking was justified.
It's also mentioned how humans basically destroyed Earth and had to send colonizing ships to another planet, but there's no deeper conversation or commentary about how that happened or why it might happen again in this new planet, the narrative is always pointed towards the whole human race being evil and being the issue, and not the current structures that make these things happen. Seems a bit shallow to me.