My modpack suggestions:
Enigmatica 6: A brand new addition to the Enigmatica series, This 1.16 modpack is a kitchen sink, but a certain mod has tweaked the ore gen to extreme levels. Good luck making fissile fuel for your SPS multiblock and your mekasuit.
The Sigma series: If you didnt know, there are 2 modpacks in the Sigma series. Sigma is a 1.14 pack while Sigma 2 is a 1.15 pack. The packs have PO3 vibes, but not without the grind for singularities. #1 Pack, dont know why it is not as well known as PO3 or E2E.
Equivalent Skies: This modpack has balanced EMC to a level where you automate everything instead of just using EMC, making the pack a lot of fun. I highly recommend this one.
Awakening: Sky of Diamonds: This pack has had a popularity surge in recent times. Its a pack made just to have as much fun as possible. This pack wants you to go overboard. Non-serious people will like this a lot.
Tekkit: The successor to Tekkit Classic. One of the pioneers of modpacks. Very broken. Exploit Everything. Go Crazy.
*My list might not be very explanatory, but I dont wanna spoil the fun for everybody!