Key things to note are that when you use the .ism/manifest path - that will return a Smooth Streaming format manifest.
Your player framework would need to support Smooth Streaming to handle that.
I'm not familiar with Plyr.io, but on quick investigation it looks like it is NOT a streaming player. Meaning it does not support HLS or DASH streaming formats.
It just says this - " Streaming - support for hls.js, Shaka and dash.js streaming playback"
So if you are using that player framework, you still have to use HLS, Shaka or Dash.js to get streaming to work.
I think that player is just a simple wrapper around the basic HTML5 video tag, which does not have streaming support on all browsers.
To get HLS from AMS, you have to add the format=m3u8-cmaf to the URL
To get DASH form AMS, you have to add format=mpd-time-cmaf to the URL
See the documentation on dynamic packaging here - https://learn.microsoft.com/en-us/azure/media-services/latest/encode-dynamic-packaging-concept
What you are in need of here is some player framework that can work in Blazor that support DASH or HLS streaming. I think your only and best choices are HLS.js, Shaka, and Dash.js.
Video.js is an option as well, but if you want to use Live streaming, it does not actually have the best performance for lower latencies, so I don't recommend it right now.