No other way to reduce heat generation other than remove some tubes but I don’t know if your amp supports that. Likely this won’t work because of bias circuits that depend on two tubes to compare. You need someone that understands the amp well.
I have an Ayon amp with 4 x 6c33c tubes and makes 400 watts of heat. cant use it in the summer. In the summer I use my Decware. I’ve got it to dialed in I may end up selling the Ayon rather than switching back in the winter.
Jerry