Kia ora!

I've been an ios user for 100 years at this point, but used to be deep in the android scene before then. I've just got an android for a work phone and am wondering what's changed in the last 10 years - what are your essential apps, settings, customisations? I've had a hunt around xda but can't seem to find much in the way of roms for my model (Samsung A04) - back in the day it seemed there was a thread for every device!

What do I need to know?