I also often long for that magical feeling of everything being new and exciting again (to you). Like the computer was waiting for you to just press the right sequence of buttons...

I obviously can't guarantee getting that feeling back in full, but I've been able to experience remnants of it by just poking around with completely unfamiliar tools/languages/servers/systems that have little to no use in business. Maybe even obsolete.

Basically, look for anything that you wouldn't be tempted to turn into a job or use to make any real money. Just enjoy it for what it is. Write hacky code. Press all the wrong buttons. Make it do things it was never meant to do. Do stupid things with it just for the sake of doing stupid things. Have fun just for the sake of it being fun.

sounds quite fun, right? I also have this impression and kinda miss that

Well, you still can experience early days of conventional programming in 2020 until quantum programming takes over in 2040 ;)