As far as I can tell, the Canon R5 is the cheapest camera that can shoot 8K (and also has IBIS, 10bit, great AF, RAW and Clog). And there is a really cheap and compact but fast RF native lens - the RF 50mm f1.8.
This 8K video was shot to assess the capability of this least-cost combo. Shot in 8K UHD 10bit All-I Clog 3. Because I did not have a 43mm (!) ND filter, this was mostly shot at f11.
This video will play at 8k if you select it. I had no problem streaming it in 8K and viewing it on my 4K and 1080 monitors .
And, no, the camera did not overheat (75 F, and in the sun).