How has movies changed since the 1980s/90s?

80s movie were cheesier, sappier, more melodramatic, often had offensive language/stereotypes.

Color grading was different back then, idk how to explain this one... Just go watch movie clips from the 80s on YouTube, they had more contrast/vibrancy and had were "grainy" image-definiotion wise.

Genres have also changed a lot... Specially superhero and horror movies

The same thing can be said about 90s movie but to a lesser extent, and (SOME) late 90s movies hold up well compared to movies from the early 90s/80s

IMO I'd say the cheesy vibe of 80s movies continued into the early 90s, but was pretty much dead by the mid 90s (same goes for other aspects of pop culture really).
Mid 90s honestly reminds me of the 70s in a weird way. There was a strong emphasis on gritty dramas and high-concept action films. CGI started to creep in more into modern movies.
Late 90s was when CGI really took over movies. Sci-fi saw a revival, as did disaster films. It too is a lot like the 70s in that regard. But the late 90s shares the same gritty mid 90s vibe in regards to film IMO, but more futuristic in terms of both vibe and aesthetic. Again, the use of CGI certainly helps.

Here's another difference I've noticed between 80s and 90s movies.
With the 80s, it always seemed like, no matter how dumb, 80s movies generally had no sense of self-awareness. They all had this very dramatic and over-the-top kind of vibe to them.
90s movies are also very over-the-top, but in a completely different kind of way. These movies tend to be much sillier, with a greater sense of self-awareness, which results in things like fourth wall breaks, pop culture references, and pointing out tropes in movies.
You can see this when you look at action movies. Whilst Total Recall and Terminator II still had that 80s dramatic self-serious tone to them, Last Action Hero, True Lies, and Demolition Man, all of which came out in the core 90s, do not, instead being very self-aware movies that sort of make fun of the genre and how played out it is. Same goes for horror movies, specifically Scream, easily the quintessential horror film of the decade.

Whilst the 90s were generally a more stripped down decade compared to the 80s, I think comedies were one aspect that got substantially more over-the-top in the 90s vs the 80s.
Most 80s comedies, like Sixteen Candles, Breakfast Club, Ferris Bueller's Day Off, and Bill and Ted were heavily character-driven and focused on the relationships between characters, and the situations they find themselves in. More often than not, they also tended to feature relatable characters in relatable settings. The 90s were the complete opposite, often with one star driving the entire film: Jim Carrey, Adam Sandler, Robin Williams, Mike Myers. The best way I can describe most 90s comedies would be that they're essentially live-action cartoons (with The Mask definitely being the most egregious example). The main character(s) do outlandish things that no sane person would do, and it's this dynamic that generates the humor in 90s comedies. There's virtually nothing about the likes of The Mask or Ace Ventura that is grounded in reality. Just very wacky slapstick humor in most of these movies.