
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.
On PvP reset, always push the first days of the season to take advantage of the ranking reset.
Even whales will be pushed back to the last spots, meaning you can take top 100-500 (depending on your server) for free gems on the day of reset.
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.
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.
Recently they switched to % rewards instead of numbers, but the rewards are still the same.

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.
Global gets way less than 100% ATK / HP for using 6 units of the same element and there is also newly added race passives.
Meta for global will be different, use this only as a reference.

As you can see, a lot of KR bros like to use full Depressed or Vivacious teams since it’s harder to counter.