Canon has the EOS R5 and the EOS R5 C cameras along with a dual fisheye 180º f/2.8 lens.  The combined weight with batteries will be 1600 grams for just the camera and lens -- gimble, etc will be extra weight.
I'm looking to see if I can build or purchase a pre-built drone that can lift that much weight as well as having a gimble that has a general purpose camera mount that will accept a Canon camera.  I am half way assuming that I will need to build something from scratch but maybe not.

What products does DJI offer that will help me achieve this goal?

Are there web site or other resources that can help me?

Hello! From DJI : M300RTK, for the payload Gremsy but only compatible with Sony ( as far as I know )

Yes the M300 or M200 will support the R5 but as @AR_Precision mentioned you'll need a 3rd-party gimbal which will likely have a separate controller and video feed (the pilot may not be able to see the R5's image or control it).

Other (non-DJI) options include drone from Freefly, Aurelia, and others, generally with 3-party gimbals as well.