The Q-SX218 is a 218 sized stretched X quadcopter meant for racing.
This frame is the second version of the frame. The first one was good but I made some small changes to improve it.

The frame is designed for 25mm standoffs. That makes that you don’t have a lot of space for your electronics.
As you want a bit more space, than you can use 30mm standoffs. I have added 30mm cam mounts for that. The came will also move 5mm up.

I designed it for the Runcam Swift and the HS1177/HS1189 cam with a lens that has a diameter of 18mm So all lenses will fit.
A Runcam Eagle will fit but as you want to use the cam protector, the cam needs to be mounted more in to the frame. This makes that as you have a stack behind, that the cam can not go to max angle. If you want that, you need to mount the cam on the back hole.
I use a Betaflightf3 fc and a Runcam Eagle now and I have my cam under an angle of 30 deg with the cam mounted backwards. The fc is mounted on 8mm dampers. By mounting the fc a bit lower, you can get more angle or use the 30mm standoffs. This raises the cam 5mm and will let you set the cam on a bigger angle.