Reading, Letters & Numbers

My son is turning 5 next month. He's very creative, loves art and is bright, emotionally as well, but still struggles with some letters and numbers, despite the supplementary work we do with him at home, outside of school. I would love to start easing him into reading and math. We read lots of books and I feel badly, because he tells me he really wants to read and he really tries. Ive never forced him and wanted him to learn at his own pace which feels most comfortable for him. He absolutely loves books. We even read three before bed on top of what we do during the day. He also says he wants to know his alphabet like the other 4 year olds in his class. This hurts my heart. I've tried many things, but he just doesn't recognize some letters still.

I've been looking around for apps which may aid him in learning letters and numbers, early reading and math. So far nothing has stood out to me and all have had mixed reviews. Some really good, some very bad for lacking things. I'd like something engaging as well, he really does love to learn in general but it would be nice.

I don't want to pay for a service and have him end up losing interest or not have enough fun features to explain things and aid him in the process.

Does anyone have any recommendations for reading/math and helping to learn letters and numbers in a fun way? Thank you for any advice!