I don't think it is possible
Whare can I Play circular chess?

The Chess Variants web site has standard Circular Chess and several other circular variants. Their user interface is a bit ... let's call it quaint. But otherwise it is a great site. https://www.chessvariants.com/play/circular_chess.html

I do not recognize it. You could try asking in this Facebook group: https://www.facebook.com/groups/208978336286023

There are several triangular chess variants. Here is one: https://www.chessvariants.com/shape.dir/tc.html
I am not aware of any that can be played online.
Anyone pls tell me how to use deckmate or circularchess follow my youtube sepehrthelittlescientist