Is the butcher block resting on the appliances or is it otherwise supported? I’ve always allowed for a 1/2” gap to let everything breath and never has a problem. If you want to rest it on the machines even 1/2” insulation would provide a temperature buffer though I still like having air movement above and below the wood.

Actually it’s a good inch and a half above the appliances due to the front face taller than top of the machines.

I wouldn’t worry at all