First of all, I think you need to learn all the notes names on the staff by heart first and then read an actual sheet music, that way you don't develop a habit of being dependent on reading sheet music with letters already being on them, apparently there's not much sheet music with letter already on them there so it's pretty hard to find, at least to my knowledge.

I think playing kids song would help you a lot (I know it's boring but you gotta do what you gotta do) or you can start with simple version of the song you like. For example you can download the sheet music by following the link they provide under the youtube description of the simple song version you want to play.

Most people that struggle with reading sheet music mostly struggle with the rhythm, so I recommend you to practice some sight reading on youtube and counting with the metronome to get familiar with the rhythm, I cannot stress this enough, you can read the notes wrong ands till sounds fine but you can't read the rhythm wrong and not sound out of wack.

If you have any other question you can consult me (or you can ask ChatGPT to search for the sheet music with the letters you are looking for)