I how many hours of sleep should I get?

You're not 93 tho

Does it really matter you already lived life. No more rules for you Mr.

I'm told that as you get older, you require less sleep 3-5 hrs should be good

This greatly varies by person, but the general ballpark is around 6-8 hours per day…

HOWEVER, if you're running on a polyphasic sleep cycle, you could run between 2-4 hours. With the "Everman" polyphasic cycle being one long cycle of about 3 hours & then 3 20-minute naps spaced out (with everything roughly 5 hour apart). "Uberman" runs with 6 30-minute naps (for a total of 3 hours per day) throughout the day around 5 hours part & the "Dymaxion" cycle with 4 30-minute naps (for a total of 2 hours per day) every 5 1/2 hours.

Most tend to run on a biphasic sleep cycle with a 6-hour sleep & then 60-90 nap midway through the day, if they choose NOT to run on the monophasic sleep cycle (where you sleep once per day).

Considering you're playing games for 20 hours (assuming no breaks) & sleeping for only 3 hours… You might want to cut back on the gaming & give yourself more downtime to take care of yourself (I wouldn't recommend going over 12 hrs / day, but you should limit gaming to no more than 16 hrs / day). However, it's ultimately up to you to take care of yourself.