Agree with all the PPs that letter sounds r next. As long as it’s fun and interesting for him, it’s great! Also, memory skills are highly underrated. So even if learning letters is rote memorization, it’s a useful skill.

if you really want an early reader:

1. get magentic alphabet letters for your fridge. play with them until your kid knows what sounds all the letters make -- that is how reading begins

2. read to them. a lot -- 30 or 40 books a day.

3. Get one of those alphabet puzzles. this was actually the most effective way to teach my kid all his letters.

I did this with older my son, he was reading in PreK3. I guess it was pretty cool, he got a head start on reading and now, at age 7 in 1st grade, has so much info in his head. now he is at a 3rd grade level.

with my younger son, i am MUCH more laid back. I don't actually think early reading is that important. second kid is still super smart and happy, absorbing things and figuring things out at a natural pace.

Once your kid can identify uppercase and lowercase letters by pointing and saying them, teach them sounds.

Look up phonemic awareness. My 3yr old (just turned 4yr old) is fascinated by his brother’s kindergarten and 1st grade distance learning especially phonemic awareness videos. The 4yr old writes better than the 6yrbold now.