I just play the challenges every day, most days I can win 3 keys (Hoeing challenge works great for a third key and sometimes I get lucky killing archers.)
I own most of the feudalife games so weeks pass by before something activates on my account. I end up with 70-80 keys to give each month.
I collected a lot of keys in 2021, I was too busy to gift them back then.
Edit: I also never traded any of the games won and I'm level 0 in a giveaway section (never created a single giveaway). It would be a lot easier to win more keys if I got a malus reduction for a positive feedback... Everything I win (if I own it) goes back to this community.