There's still a decent amount of variety in top level, in my opinion. Yeah ballpoint and tacticooler are seeing a lot more usage right now, but splash isn't required on any teams at this point. Much better than launch with almost every team being 1-2 sloshing machines and 2-3 splashes.
Brellas are a weaker class right now, as a person who played brella competitively for years. Tenta Sorella Brella is the main one, which I've still seen some of (the JP region has some players who have gotten tourney results with Tent!). Chargers and stringers I still see a good chunk of in most levels of play, I think it's just hard to fit on a team when inkjet is so powerful with ballpoint. You can definitely make them work in a comp though, especially in mid-level!
As far as rollers: here is probably the best roller in the NA/EU regions right now:
https://twitter.com/Volty_carbone. Volty is a player for Alliance Rogue, and has gotten tons of wins against top teams in North America, such as Starburst.
To find more competitive gameplay of weapons you're interested in, try
this website. You can filter based on which weapon you want to see, and there's a ton of tournament matches covered with most weapons in the game! The official tourney streams only catch one team out of the dozens that play in them, so these individual perspectives may be more of what you're looking for.
Don't give up in comp splatoon, there's a lot of downers with what's considered ""meta"" but if you approach it from a mindset of progressively improving, you'll go places!!