I got a 3D printed bracket from RC Kleinkram which mounts pretty solidly to the chassis
https://www.t2shop.de/epages/6174632...%2F08-3DRC-023
Then they also do this
https://www.t2shop.de/epages/6174632...%2F08-3DRC-003
And there are some 30mm versions if you want that.
https://www.t2shop.de/epages/6174632...ch_Marken/3DRC
BTW, a solid mount is more likely to damage the fan. Depending on the orientation of the fan.
I've run several fans (, Hudy, Hobbyking etc) in these brackets (i have 3 or 4 of them, buggy, 8th, TC) and not yet had a fan fail. I use VHB tape to attach them to the chassis. SO they get a little damping..