It is July 2020, and gcc 10 is ahead of the pack in terms of C++ 20 conformance. Clang is a close second, and Microsoft Visual Studio is trailing in third place.
In spite of the trailing compiler, Microsoft offers a slick IDE called Visual Studio Code, which runs on Linux, Windows, and MacOS. Got a Linux or macOS desktop and need a temporary Windows development environment? Download a temporary Windows development VM.
For some extra help, check out the Boost Libraries, which are multi-platform and multi-version.