My son picked up his letters from me reading the Dr. Suess ABC book. Not sure when exactly, but he knew them all at 18 months when I bought him magnetic letters on a hunch he knew them already. Around 20 months I sang that song the popular fridge toy sings (the b says buh, the b says buh, every letter makes a sound the b says buh) for each letter and DS picked up all the sounds the first time I sang them. After that I made a few words with his magnet letter and sounded them out for him. I never asked him to do anything, he watched and listened to me because he was interested. Next thing I knew he was spelling words with his magnets on a daily basis.
DS didn't actually start reading until around 3, presumably when all of the aspects of reading readiness were sufficiently developed. He would get all into reading for a time... and then completely lose interest. Each time he would start reading again he would be ready for a new level of books. Other than encouraging him to finish a book if he started it, he's mostly been in charge of his own reading progress other than me telling him the sounds and showing him how they form words that one day.
We didn't have any electronic toys when he was little and he never even saw a screen on in our home until 22 months when I got a tablet for Christmas. He loves screen time, but now, at 6, it's still pretty limited. Once a week he can watch a movie and other than that we alternate days he can use the screen with days he plays outdoors after school. Most days he gets no screen time.
Around 18 months his favorite toy was Keva Planks and he build all sorts of things with them. He also loved Play Doh, Duplo, and puzzles. I took so many pictures of the things that he made (green poop with play doh!?!) and I'm very glad we spent that time playing together without screens.
There's nothing a screen can teach your child that you can't teach better. Building with blocks is an especially excellent time for presenting new vocabulary that they pick right up on because they are engaged. They learn physics and geometry without even knowing they are learning anything.
BTW, I too was told the class they had for my son for K was full of "smart kids just like him". Total rubbish. They had no clue where he was really at. Even at the pediatrician where they know him well and his file includes his IQ results (along with info about his disabilities) they get all bent out of shape about the least impressive stuff. Last week he was getting measured and they asked him to take his shoes off and he insisted on taking his socks of too because he was concerned about the measurement being completely accurate. They couldn't believe he said accurate. This was so unimpressive to me that it took me a moment to understand what they were fussing about. I guess I learned that most 6 year olds don't use that word, but I still find it hard to believe.
I guess what I'm saying is that it doesn't matter what your child is doing, how many times you have told someone they are doing it, or what test results you have in hand... it's like all of that info just hits a brick wall of incomprehension. Then they act so surprised when your child does the least of what they can do. We found a tiny all gifted school where they totally get it and he fits right in. We will never look back. Hopefully you guys will find your place as well. Good luck