I think the article focuses on JS execution CPU usage and its savings on M91, so it doesn't count for all the CPU Chrome uses.
About the split, it depends a lot on the type of content.
If you're visiting a statically generated page, that's negligible on the server and puts the strain on the client: Document formatting, JS execution, image rendering, etc.
If you're dialling into a 10 person google meet, your laptop fans will start spinning fast, but also the server needs to transcode/serve the video (well, multiple servers, multiple services most likely) so heavy on both sides.
If you're consuming some elaborate web dashboard with high data requirements, then the strain is probably on the server side.
About the split, it depends a lot on the type of content.
If you're visiting a statically generated page, that's negligible on the server and puts the strain on the client: Document formatting, JS execution, image rendering, etc.
If you're dialling into a 10 person google meet, your laptop fans will start spinning fast, but also the server needs to transcode/serve the video (well, multiple servers, multiple services most likely) so heavy on both sides.
If you're consuming some elaborate web dashboard with high data requirements, then the strain is probably on the server side.