Endgame is terrible. It's not even trying to hide it.
Just to give an idea, you have to cook a bunch of different pam's harvestcraft meals in that endgame, along other sins such as nonrenewable blocks to hold onto, in which losing them will lock you out of further endgame progression.
Do not recommend this pack. It's too obvious that the endgame is shit.

TL;DR: Nice pack, fun and quick to play, not really that overpowered, a bit grindy at the end.

Early game

The pack starts as a relatively normal skyblock modpack but turns into something special really fast.
Instead of relying on ExNihilo or other forms of skyblock ore generation, you can access the mining dimension where you can get all ressources. Since ProjectE is in the pack, you don't really have a reason to stay there for long though. Same goes for Tinker's Construct. I crafted a total of maybe 2-3 tools with it, one of them being a bow for the lategame. As soon as you got a basic farm for EMC going, the tools aren't needed anymore and can be replaced by ProjectE Red Matter Tools. The pack then continues with some basic tech in the form of mekanism.

Mid game

From my experience, the midgame starts as soon as you get a good EMC farm. The pack suggests chickens, which is easy to automate, but takes forever to setup due to the breeding speed being extremely low. The midgame itself mostly consists of playing through different mods, building multiblock structures and automating ressources that don't have EMC values. The structures are fun at first, but turn pretty boring after building 2-3 of them. Due to changed recipes, playing the mods is required to some extend, but some stuff can be skipped by using loot creates which can be bought with the coins you get from quest rewards. Some of the mods aren't required for the midgame entirely and are just relevant for the endgame quests.

End game

The endgame is the least fun part of the pack in my opinion. Due to an oversight in the quest system, I was able to get a creative storage cell pretty early, which saved me some time waiting for crafting processes, but even getting the items once to dupe them took forever and was tedious. The quests require absurd amounts of items. If you want to finish the pack 100%, you have to craft a ton of different Pam's Harvestcraft meals. The automated crafting tasks take long as well, because for most you need ressources which can only be obtained by multiblock structures which have a substantial crafting delay that adds up quite a lot. If played correctly, the last items are creative ones, which by this point you don't really need anymore (however, this is the same for most packs).

General thoughts

In general, I feel like some of the mods in the pack aren't really fitting, but I think this comes down to the pack not having a clear focus or goal. The pack name suggests that the goal is becoming overpowered, but I didn't really feel overpowered while playing. You can reach the EMC limit pretty quickly and from this point, all EMC farms can be turned of since there just isn't a way to spend this much EMC. Until the last quest, you still have to automate crafting tasks and craft manually. For me personally, the endgame mostly consisted of playing the mods that I skipped in the midgame because they just existed but didn't offer any meaningful progression at the time.

I think the pack is fun to play, especially in multiplayer if the crafting tasks can be distributed. It can be played through relatively quickly and introduced me into some mods I didn't know before.