Are there any audiophile level surge suppressors that do not add any conditioning or filtering?
The best surge suppressors are low pass filters. The low pass filters slow down the surge to give the surge suppression gear time to respond, so no, not really easy to do one and not the other. Based on the Wirecutter articles I often quote and others, all the best surge protectors (in terms of let through voltage) include filtering.
Whole house surge protectors are important, but the let through/clamping voltage is significantly higher than a good surge protector. I wrote about it in too much detail here. I've been in the cross hairs of 3 different hurricanes this year and suffered power issues each time, so my sensitivity to risk is a lot higher for me than many readers here.