About g-synx

Greetings, friends. I'm interested in my opinion on the use of settings in games such as Nvdia Reflex, Nvdia G-Sync and v-sync. In which cases is it better to include all this? My assembly is LG oled 28" 470hz, 7800x3d, 64gb, 5070ti. I play mainly AAA, sometimes dota2/cs2. When g-sync was turned on, flashes (flicking) were sometimes observed, so I initially turned it off. Thank you!