We’re trying to build on Bitcoin Testnet4
Testnet isn't meant to "build on".
ckpool is making it nearly unusable.
What makes you think it's ckpool that's doing this?
You may want to read
Testnet4 Mining (Discussion) (to start):
The areshole who is abusing testnet4 is better with mining empty blocks to avoid any block being invalidated if any transaction was not right
I would have guessed it's because smaller blocks can be broadcasted faster.
This is incredibly frustrating for the developer community. Either this gets fixed, or we seriously need a new testnet.
I've seen some discussion about how to improve testnet, but all suggestions have drawbacks again.