jansevr
1 kW
Sabvoton has a 36fet controller that is capable of 200a battery and 450a phase. It might be possible to get it unlocked for even more since the 24fet can do 200a unlocked. Although this is only 90v or 20s max it is probably the best controller available for a hub that I know of.
https://m.aliexpress.com/s/item/32827301253.html?trace=storeDetail2msiteDetail&spm=2114.12010612.0.0.53c18534zc2Jb0#autostay
Also i believe sketch has made custom hubsinks for a 273, he could probably do another fairly easily if you ask him. FF and hubsinks should solve your heat problems.
https://m.aliexpress.com/s/item/32827301253.html?trace=storeDetail2msiteDetail&spm=2114.12010612.0.0.53c18534zc2Jb0#autostay
Also i believe sketch has made custom hubsinks for a 273, he could probably do another fairly easily if you ask him. FF and hubsinks should solve your heat problems.