What is the ruling concerning the days I intentionally broke my fast in Ramadan after masturbating, knowing that their number ranges between 3 and 6 days and that I sometimes fasted without praying? And how do I make up for the Ramadans I missed?

Remorse over missing prayers is an indication of repentance, but the missed prayers must be made up. The majority of scholars hold that this is obligatory. As for making up the days you missed fasting, you should estimate their number based on your best judgment. The six days mentioned by the questioner must be made up. However, you are not required to make up the days you fasted without praying.