What should I look for before buying a TV?

Hi Everyone!!! I am looking for a 50 or 55 inch Google/ Android TV. I don't have much knowledge about this. I want to buy one with 4K quality. Which is better LED/QLED/OLED or any other that is better than these? What can I get for a 50k budget? Which company has good TVs? I primarily use it for watching general TV channels, OTT content and youtube but not for gaming. My parents also use it for TV channels and youtube. Please share some insights and also suggest good brand and model. PS: Can anyone also tell me when there will be more offers on TVs? During Ugadi? Or some other festivals? Which stores have good TVs in VIZAG? Edit: Now I learned that I won't get OLED/QLED for 50k