Seeking Understanding: Prayer Practices and Their Sources

As-salamu alaykum, friends. I hope you're all well. I wanted to humbly ask if someone could kindly explain to me, without any judgment, why some communities perform a form of prayer three times daily, while the established practice from the Quran and Sunnah is five daily prayers. I'm trying to learn more about the origins of both. Honestly, I've been focusing on trying to follow the Quran and the Prophet's (PBUH) example directly in my own life. I've started performing the five daily prayers, but when I talk to my family about it, they often get upset, which really hurts because I'm just trying to seek what's right. Could someone please help me understand how these different understandings of prayer came about? I've read that some believe religious interpretations can change with time, but I hold that the guidance in the Quran and the acts of worship are timeless and fixed until the Day of Judgment. I'm just a bit confused and looking for some gentle clarity.