Got hacked, can someone help clarify some stuff please

So i just got hacked on steam, still trying to figure out how. Havent clicked any links or downloaded any new in recent times, but still lets just go with the argument that i was stupid and i fucked up somewhere and thats why i got hacked. Can someone please help clarify a few things so i can sleep with a peaceful mind.

1. How did someone get access to my account ( Even if they got the Password somehow) if
   1. I have steam guard enabled and never gave my OTP to anyone
   2. My steam guard enabled phone was with me the whole time
   3. My gmail is not hacked and i never got the notification that a new login is seen
2. My items were SOLD in the community market for very small price 11-20INR
   1. If Steam guard "confirmation" message triggers when you list ONLY for items that are listed at Rs 100 or more, whats there to stop a hacker when selling costly items for 10-12 rs
   2. Whats the use of even having a confirmation message pop-up on steam guard if your items can be sold by a hacker for 10-20 Rs INR without triggering any checks?

I still havent figured out how i got hacked, have already raised a Steam ticket but these questions have been bugging me like crazy. Please help out with answer assuming im a total idiot in these stuff.

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First time ever getting hacked and its really messed me up. Have had 2FA enabled for everything including Financial stuff, dota and much more. But still got hacked. I regularly run Malware bytes and defender for checks and dont use same password everywhere. Any additional stuff i can do to increase my safety is a welcome advice ill happily use.