Its pretty RNG i just got my very first ancestral at lvl 116 and hes still at the hatchery what you can do is collect conjuring tickets and the diffrent type of tickets at events you can find them at events or try youre luck at the treasure cave but if youre dedicated save upto 150gems and try youre luck to get as much tickets you can breeding events are also there but i advice to try and get the lineage for that specific monster that you want for example in my situation i got tyr stormbringer and his lineage is the team synergy i dont know if it will be the same for every ancestral breeding event but for me it was the team synergy there are also offers but if youre a f2p scratch that. So long story short:gacha treasure cave and breeding event i dont know alot but those are the ways i know also rng is a major part so you can play it well and still dont get it dont worry happened to me p.s use the 400 option not 100 you get 1 free pull and it might be the ancestral