Could you share your routine....how much you practice? Do you just do the online course? Do you work on one song at a time? Is there theory included in your syllabus? So curious to hear what the routines of others are. Not to compare - but to learn and try new ideas.
I started through the platform HDpiano and by watching and replaying videos on YouTube (synthesia). I challenged myself by choosing quite difficult pieces, which I do not recommend. What I do recommend is to play pieces that you really like.
1st: Yann Tiersen - Comptine d'un autre été
2: Johann Pachelbel - Canon in D
3: Yann Tiersen - La Valse d'amélie
4: Ludovico Einaudi - Nuvole Bianche
5: Schubert - Ave Maria
6: Yann Tiersen - Comptine d'un autre été [extended version]
So in doing so, I started with synthesia up to and including Schubert from Ave Maria. Partly via sheets, partly via synthesia. Via HDpiano, the pieces are divided into, say, 5 parts. You learn the left and right hand separately. Then combine them. Start slowly and only increase the tempo when you can play it a few times without any mistakes. On average each piece took me about 2-3 month's to learn. I did practice 1 hour a day (4-5 days a week), repetition is very important!!. Currently, I have returned to the basics. Learning notes and scales. If you would like to see more, I have done many uploads on my YouTube channel. Best of luck with your piano journey.