In the certification of theory classes there is a setting given to the school for a minimum time to spend. EASA PPL remote learning theory can typically be done in 4 weeks, assuming 36 hours per week learning and including 10 hours front face class. If you focus, it can be done. But, if you are doing this besides regular work, it will take much longer in total hours! I did my theory while working full time and it took me about 6 month to pass all in one. The key is, as always, focus, focus, focus.