I can no longer cast iTunes to my TV

So here's the thing.

I use Windows 10 and have a Samsung TV.

Casting/streaming iTunes to my TV no longer works.

I have been through this with 2 Apple representatives. The first had no idea at all. It was escalated to a 'higher' level, Queenie. She screen shared but was not able to get the bottom of the cause. She asked me to give her a few days so she could investigate the problem. 3 days later....

Her answer: It's not an Apple problem. There is possibly a problem caused by the update from Microsoft. So please call them. Apple essentially wiped their hands of the issue.

I contacted Microsoft, we screen shared and they had no idea why this would come about.

I have the latest iTunes, reinstalled iTunes. All devices have been restarted, updated or reset.

All streaming and casting from my PC to TV works fine.. EXCEPT iTunes.

When I open iTunes the Airplay icon is there but as soon as I play a music files or video file it disappears.

I do remember there being 2 volume sliders, I think when Airplay is engaged ???

How can this NOT be an Apple issue and one that they would like to address?

So.. I am looking for a solution.

Any ideas?

Would love your help.

Michael