For XINA50 you can use unfiltered tick by tick data LVL 2 from KINETICK. total costs
55 basic fee
20 Market Depth for LVL 2
48 Singapore
123 USD total

CFFEX is not easily open to foreign traders, which is a shame as there's more than just financial futures which are interesting.

Anyways, you don't need to trade CSI300 futures directly (although resourceful people can find ETFs on HKEX), just trade XINA50 on SGX.