There is no a modern day equivalent. Not because of availibility of hardware or software (both better hardware and better software are widely available at trivial costs nowadays), but because the world around us has changed. Specifically, the experience needs to compete against the limitless other distractions from the internet.
Here's a simple simulation of the 1980s experience: https://virtualconsoles.com/online-emulators/c64/
If your kid is like most kids, they might spend 20s on this before they get back to their Youtube/TikTok/Instagram/Roblox fix. Or maybe a few hours at best if there's a very enthusiastic adult sitting next to them explaining everything. But they'll probably be back at their regular internet distraction as soon as the adult is gone.
For a decent recreation of the 1980s experience, you'd need to shut the kids off from the internet for some extended period. But even that is only an approximation, if they have any contact with other kids.
Exactly, this means we are living in a very weird period in history. Right now there are people who know a lot about computers, for the sake of "they looked cool in the 80s/90s". People born in the 70s and 80s are ~5-15 years removed from pension or disappearing from the workforce. Already there are no 20 year old and few 30 year old geeks.
3% of us are disappearing every year. And that's just not going to stop.
There are lots of things to do. Lots of programming things mixed with other domains like music. Just one example: https://sonic-pi.net/tutorial.html
There are tones of SBC, plus arduino. Calliope and others.
Scratch for little kids, lego mindstorms.
I know boys between 11 and 13 learning Python, programming some simple games.
There are also lots of robots and HW.
What there is not (or I do not know it) is something like the microcomputer of the 80s.
That is a little computer which can do graphics, sound, little games, and even control peripherals with a very simple language. I would really have something like that.
And with which SW?
I mean, I can do “anything” with C++, but doing what I did in Basic in 100 lines would need 1000, plus downloading libraries and frameworks and reading several 500+ pages manuals. If your kid is not an english native speaker, you have yet another hurdle.
maybe check out PICO 8. It's basically a VM (self styled fantasy game console) that runs on a bunch of devices and an active community. https://www.lexaloffle.com/pico-8.php
A similar project that I'm eager to hack on (or maybe try my hand at implementing something similar in WASM) is the UXN platform. https://100r.co/site/uxn.html
And if we're already talking VM platforms to explore, there's no reason that someone who doesn't want to do software professionally can't get a lot of enjoyment from some basic syntax knowledge and making modifications to software they use every day (whether that's writing a userscript in your browser or exploring your favorite game via mods)
Here's a simple simulation of the 1980s experience: https://virtualconsoles.com/online-emulators/c64/ If your kid is like most kids, they might spend 20s on this before they get back to their Youtube/TikTok/Instagram/Roblox fix. Or maybe a few hours at best if there's a very enthusiastic adult sitting next to them explaining everything. But they'll probably be back at their regular internet distraction as soon as the adult is gone.
For a decent recreation of the 1980s experience, you'd need to shut the kids off from the internet for some extended period. But even that is only an approximation, if they have any contact with other kids.