as a f2p player the material and resin problem is mostly at the start from the initial surge of all characters/weapons, after you spend your initial chunk of primogems from quests, levels chests etc you will probably get something like 20? pulls per month, meaning you will be get like 1 new character a month probably if you are completely f2p, and then the resin resources wont be a problem once you have levled up most of your other characters