its just luck, but of course the more 80 stamina maps you do daily, the more gacha seeds you get and therefore more bond crystals

unless theres a more cost efficient regular map for gacha seeds, but you wont get any life crystals.

3 star knights are also fairly common and those sell for 20 bond crystals each so the primary monthly supply is actually from the bronze knights for the standard f2p player, unless you buy the weekly Thursday gacha deal which typically has 5-6 stars on sale.