I dislike PVP in most gacha games, but Trickcal handles it pretty well for casual players who are just looking for extra currency every day. There is no RTA, just one basic PVP mode where everyone in your server fights.
As a casual player that hasn’t even built his characters, I get around 1,500 gems per season just with the daily fights. Since it’s auto battles, it takes 2 minutes to do all 5 of them so don’t forget.
Outside the daily rewards you get for climbing to higher rankings, there are also season rewards distributed every other week (I think it’s bi-weekly, I’ll confirm later).
Just for participating in PVP you will get 500 gems (5 singles). There are no reasons not to participate in PVP for the first couple days and then ignore it for free rewards after you get stuck in the rankings.
There is no perfect team since it depends on the current patch, newly released unit, and who you have built. Most players focus on elemental teams, since you get a 100% increase in damage and HP if you are using 6 units of the same element.
As you can see, a lot of KR bros like to use full dark teams since it’s harder to counter. This also applies to a lot of the PVE content, since you will see elemental teams play a huge role in this game.