Completely agree! We build our .NET projects in a similar way too.
My current SaaS company has 8 web projects and 1 core project. Some of the web projects are SPAs using BFF and others are APIs for customers or our mobile app. They aren't tiny sites. We're up to ~500 controllers. All in a single repo and automatically deployed as a monolith. We have a super small but very productive team which we attribute to this simple design.