Here are a few ideas for cutting channels in ICF foam blocks in order to run electrical wire and plumbing pipe. The method I used most, and recommend, is the Angle Grinder with a Chainsaw Disc.

Knife & Reciprocating Saw
https://amzn.to/3peKOiF
https://amzn.to/38lclYS

Electric Chainsaw and wheel
https://amzn.to/3mDnWaN
https://amzn.to/2KBOKLf

Angle Grinder with Chainsaw Disc (this is the cheapest and best option)
https://amzn.to/3h7Wj8O
https://amzn.to/37yRsKs

Router
https://amzn.to/3nwsqRP