My friend sent me a gift card which I used to buy a game in a limited account. Will that change the account's status? The game was over 5 USD btw
Unless it was a physical gift card then no. Adding funds is enough to unlock an account as it doesn't have to be spent but if it was sent to you then the sender is the one who spent the money on the card not you.
Physical cards still work as they don't really know who actually paid for the card but they are also currency locked so can't be given to people in other regions.
No
https://help.steampowered.com/en/faqs/view/71D3-35C2-AD96-AA3A
Depends on how your 'friend' sent you the gift card.