So... I finally traded up to 20 keys from almost nothing.
Took a little while, but I did it
I did cheat a little bit by buying 5 keys but that was after I had traded up to 3 keys and it would have just been more grinding at that point
Honestly the only advice I have is to just buy 10 keys and start buying unusuals if you've tried out low tier trading, it's just a really grindy and tedious trip to get out of it and most people quit before they can even start to make money
Any low tier traders seeing this, keep going and maybe one day you can buy that Burning Flames TC :)