As I said in a previous post, there can be little doubt that, objectively speaking, Open Sicilians (2.Nf3 and 3.d4) are best. I know there is a lot of theory to learn, but correspondence chess is ideal for that. Since I started on this site, I've considerably increased the proportion of Open Sicilians I play OTB.
If you want to do it gradually, you could start off with a 'hybrid' repertoire. For example after 2.Nf3 d6 you could play 3.d4 and learn how to play against the Najdorf, Dragon, Classical etc. (The Fischer-Sozin might be worth considering, since it can be used against several systems.) Against 2...Nc6 you could play 3.Bb5 and against 2...e6 3.c3 (both quite respectable anti-Sicilians) till you have the time and confidence to try Open Sicilians against these too.