I fitted to my Newtonian a fan which blows air up the tube, the rationale behind this is to break up the boundary layer in front of the mirror, a while ago I wrote an article which is found in tutorials on cooling Newtonians which might help.
https://britastro.org/2022/newtonians-are-cool
Gary Seronik has written a couple of very useful articles on cooling and condensation which might be helpful.
https://garyseronik.com/beat-the-heat-conquering-newtonian-reflector-thermals-part-1/
https://garyseronik.com/beat-the-heat-conquering-newtonian-reflector-thermals-part-2/