For now, it remains to be seen what sort of performance one can expect from Microsoft xCloud web. One thing is for sure, and that users won’t be getting 4K streaming until the company upgrades the infrastructure from using Xbox One S server blades to using the Xbox Series X equivalent.
This version is currently limited to Chromium based browsers like Google Chrome and Microsoft Edge. Microsoft may have a public preview of xCloud web coming “in the spring”, which is between March and June. Though it will likely only be available in markets where the service is already available. Which likely means Malaysia will be left out.