Full-Frame 4K Anamorphic Video on a Budget
Nikon Z 6 + Canon EF F2.8 pancake lens + adapter + SLRMagic anamorphat 1.33X/40 adapter. Wow, that sounds really complicated and cumbersome. But in fact the lens/adapter combo is about the size and weight of any of the Nikon Z FF lenses. IBIS takes care of stabilization, and the AF works perfectly.
The lens is $199, and is one of Canon's sharpest. The anamorphic adapter is $399. Shooting anamorphic 4K full-frame video handheld is as easy as shooting regular video. No special settings are needed. This combo works with the Panasonic GH cameras or Sony cameras, or any full-frame or APS-C camera as long as you have an adapter for the Canon EF lenses (this particular lens works best with the anamorphic adapter).
Editing is easy - just set the pixel ratio to 1.33. Edit normally and render at 4K (assuming one shot in 4K).