I've been seeing the start of it. Earlier this year I saw the trailer for some game, I don't know what kind of game it was (I think a puzzle game or a Breakout/Arkanoid clone) but one of the big gimmicks was that it had a Y2K aesthetic. Fonts, color scheme, artstyle, etc. were all reminiscent of interfaces and ads from the early 00s. Later in the 20s, I expect that we'll see more of this sort of thing, maybe a Stranger Things-esque TV show. Maybe we'll even see a resurgence of fashion trends like emo and skaters.
But expect whatever nostalgia pandering we get to be shallow like in previous decades. 90s pandering was mainly "dude member dunkaroos and cartoon network and the ps1?" even though there was much to be said about the spirit of the times. Like how it was the last decade before the internet permeated everything, before 9/11, the Patriot Act, terrorism this and that, etc. Individual people may have talked about it, but you'll never hear a word about the spirit of the times from the media. Unless it's to get a punch in on someone politically.
00s nostalgia will be similar. Apple will probably make a throwback iPhone that looks like their first iPod. 2021 will be Windows XP's 20th anniversary, so MS might make a dumb color scheme or something that makes Win10 look like XP. And then they'll disable it a month later. Food companies will bring back some of the stuff we slurped and munched on for a short while. But you'll never hear a word from them about the wild west days of the internet, the pre-smartphone era, how 90% of the internet wasn't run by a handful of corporations, and ESPECIALLY how everyone and their mother wasn't whining about political bullshit 24/7. Hell, even now you get ridiculed for wanting that last one back, they call you a nazi or an incel or whatever this month's boogeyman word is.