Those urls are for whatever way the stream is set. Usually it would be H264 or H265. Only the sub stream of a Hikvision camera can be set to MJPEG. Possibly the third stream could be set to MJPEG but that's only available under certain circumstances and not via the NVR.
The likely issue, even if you switched the sub stream to MJPEG, is that the url has admin:password in the url which gets blocked by most browsers as it's sent as plain text over http. That's an issue for web based dashboards (and the reason I'm using HD+). The workaround was to use another app that acts as a web server such as Blue Iris, Tinycam and others. They can re-encode the H264 stream and serve it as MJPEG without the credentials needed.
For Hikvision there are also other urls to get a jpeg. That can be used as an image tile and you just get the dashboard app to refresh it every x seconds:
http://admin:password@ip_address:http_port/ISAPI/Streaming/channels/2/picture
where 2 is the sub stream image, 1 for the main stream (or xyy as in the other post if connecting via the NVR IP address)