The possibilities of a canal trough the Kra Istmus has been dicussed for a hundred years or more.
It has been brought up again, but now as something that has to do with the competition between India and China:
https://www.hellenicshippingnews.com/china-backed-thai-canal-potential-next-front-in-india-china-conflict/
That didn’t stay relevant for very long:
One may wonder if it ever was relevant, or was just misinformation (propaganda) put out by somebody with an agenda.
A Canal across the Kra Peninsula would be even more of a potential choke point than the Singapore/Malacca Straits in case of a conflict.
(Only one country to intimidate/control in stead of three)