I was a maintenance tech, then a headend tech, for Comcast for 39 years before retiring in 2016.
Most 2-way splitters will lose more like 4 to 4.4 dB at the higher frequencies where many cable modems have their downstream channels. Not that this is a killer, but your actual loss with 2 splitters in cascade is going to be 8-9 dB in the 500-600 MHz range, rather than the expected 7. (3.5 + 3.5)
Antronix is a very good brand, along with Regal and RMS,