(Azure DevOps PM here) Test Manager comes with VS Enterprise, VS Test Professional, MSDN Subscriptions and is also available for direct purchase through https://marketplace.visualstudio.com/items?itemName=ms.vss-t.... You are welcome to take your pick from what suits your needs.
As a subscription, it's more per month than Visual Studio Professional. As part of VS Test Professional it's almost twice as much for the first year. And you can't really do any test plans without it so its a huge part of DevOps that is just unused for us, unfortunately.
It just strikes me as an odd thing to put on a luxury tier like that. Reiterates that quality and testing is often an afterthought rather than something everyone should include. If MS wanted the revenue they would put something the most senior higher paid developers wanted rather than the testing team.
True, but I thought the goal of Azure DevOps was to be a complete package solution. And so while all the pipelines and code and work items are stored there, it would be a pain to keep test cases in something else. And why no integration with Excel?