Sky: Children of the Light

A lot of cosmetics and some event quests are available in limited-time seasons. Although event quests can generally be experienced for at least a week and only require a couple hours per season, obtaining every cosmetic requires a mix of spending money (for the season pass) and daily grinding.

One of the in-game currencies is “hearts” and aside from a few very limited supply, they can only be obtained by your friends gifting you one, at the cost of some of their main in-game currency.

The main game's “story” can be reached within a few hours, but extra levels are released from time to time. The real issue, though, is the cosmetics that get released each “season” and require a mix of grinding and paying to get.

The main in-game currency can be bought or earned by playing. There are diminishing returns and a daily cap, which takes a few hours each day to reach.

Some limited-time cosmetics (usually a few weeks) are sold against real money. Other cosmetics are unlocked by purchasing game with in-game currencies during “seasons”, and getting all of them requires purchasing a season pass. Once a season has ended, some of those cosmetics come back for a limited time once in a while (for an increased in-game currency price), and some cannot be obtained again.

Yes, there are daily quests and log-in bonuses. They are not strictly necessary but are one of the main ways to get the in-app currency.

Some cosmetics are for sale exclusively in exchange to real money, but most cosmetics are sold in exchange to in-game currency that can be obtained either from playing or in exchange for real money.

It isn't "truly necessary", but yes.

But only if you want to truly finish it 100%, which isn't actually necessary for enjoying the game itself.

Overall the social aspect of the game induces friendliness and collaboration. But there's always FOMO, particularly about seasonal content.