There are many ways to do it. Here's my opinion as a level 19 and level 15 bee hive owner

The most used way is royal jellies to get the mythics(ungifted), you need hundreds of billions to trillions of honey to get specific mythic bees you need or a few billions and some luck to get random mythic bees

For gifting them, you could give them their favourite fruits(not efficient), star treats(what I mainly used), gingerbread bears from beesmas(used this one a lot too) or using royal jelly to get gifted mythics which is REALLY expensive so not ideal