Chris McNulty Saying that SharePoint Designer workflows are deprecated is reasonable, PowerAutomate and LogicApps can do almost all the things the existing workflow engines can do. However, they are not directly comparable, and there's an enormous difference between not adding new features to, improving and supporting something and disabling it entirely with next to no notice.
It's hard to see this as anything other than a bare-faced money grab, and at a particularly callous time when many of your customers are already bleeding.
The old WF engines were essentially free to use with your license and the new methods are significantly more expensive to run.
I'm not really all mad that you want more money, but I'm livid that you think it's ok to disable a feature that is widely used on 3 months' notice. Microsoft (and perhaps even you personally?) promised at Ignite 2019 to support the traditional workflow engines until at least 2023. It's simply not enough time for already stretched IT departments and consultancy practices to replace all of them. We will get our customers on the new platforms, but it's not that long since the new stuff became a viable replacement; customers and consultants need more time.
I sincerely hope you reconsider at least the timeline, because if not, it's frankly one of the more despicable things Microsoft has done to it's customers in recent times.