So I started using Firefox in my early teens around 2010, I didn't know/care about online privacy etc and had no idea what open source was, I just picked it because I liked the look and theming options more than Chrome at the time.
I then kept using it because it's what I knew and I can be stubborn to change sometimes. Around 2016 was when I started looking more into online privacy and FOSS stuff it kinda just reinforced my existing use of Firefox.
Recent actions by Google with their anti-adblocking campaign and Manifestv3 have just made me dig in my heels more.