Thanks for the feedback, I'm glad you're finding FusionAuth useful. Definitely understand your position. I'm a big fan of consolidated tech stacks wherever possible.

As of right now, we have no plans to support SQL Server. To remedy that, I can see three paths.

• You could file a github issue detailing what you'd like to see (which version of SQL server, etc) in more detail. https://github.com/fusionauth/fusionauth-issues/issues This has the benefit of being free and relatively low investment. It has the downside of not actually guaranteeing that this feature/change becomes available. We rank feature requests based on community input as well as customer feedback.
• You could take this on as a community project. We have other community projects (the helm charts, for example). From googling, it looks like there are several mysql->sqlserver or postgresql->sql server translation projects. You can find the schema for FusionAuth here. If I were doing this, I'd convert the schema, pop in the MS SQL Server JDBC driver to the tomcat webinfo directory and give it a go. This is obviously a heavy lift, but it's an option. If you documented that, I'd definitely read/share/promote that blog post.
• You can engage us and see about a professional services agreement if you have budget. If you're interested in getting an estimate on this, please fill out a contact form: https://fusionauth.io/contact

Here's our general roadmap guidance, which is probably worth a read: https://fusionauth.io/community/forum/topic/172/the-fusionauth-roadmap