I2C Radio link rework

We have 2 controllers controlling many lights. We connect about 100 controllers via a repeater to the I2C bus. 2 controllers we need to connect via a radio link to the I2C bus. (100kHz CLK) We use RF-NANO. Attached is the block diagram and the program we use. With our testprogram we are able to send the data to the slave. (We do not need to know if it arrived). But with the real world it does not work. I measured with the scope, it shows we send with about 100kHz the data over I2C but it seems to be received with only 75kHz. In my opnion it is too slow for the mass data. But I do not know how to make it fast enough that it sends just what arrives. Let say the adresses are 22 as in the example we do not recive all data. The radio link shall be jsut the replacement of the cable, fully transparent, just forwards what comes in on I2C, no matter what it is and how big it is at >100kHz.