You could do a nice riff on the scene from the original where Doc marvels over the camcorder by having Marty show him the movie he was recording and then have it turn off because it’s out of battery, and of course Marty has no idea how to make a USB charger, so it’s dead for the rest of the movie.
(from the linked thread)
Could also do a nice variation on the original by having Doc be a cynic and not the least bit surprised by this.
I think the biggest challenge to such a movie is making 2021 Marty cool and capable compared to the kids from the past. 1980s Marty is cool compared to the 50’s kids (particularly his parents, but all of them). He’s in a rock band, he’s capable on a skateboard, he’s independent and scrappy.
When we talk about the cultural changes between the 90s and today, things like “plans are fluid” and “we can contact anyone we want at any time, or have information at our fingertips”… those don’t make you cool compared to the past. You get some fun fish out of water moments when the future kid is without their toys and internet, but that’s not enough.
One plausible avenue you could take is that 2021 Marty is an influencer/youtuber, and uses his film/marketing skills to do something cool. There are lots of teenagers today with filmmaking skills that would rival professionals in the 1990s, and the That’s one way in which someone in modern times could inspire 90s kids to all think he’s the greatest.
Chef’s kiss.