It's no longer located under Preferences > Projects > .Net Runtimes and I can't find this setting anywhere. Can someone shed some light on this?
This feature is disabled by default now since it can cause problems when building projects with the older runtime. To enable it you can set the RUNTIME_SELECTOR environment variable.
Then open Visual Studio for Mac from the command line.
You can probably avoid having to run VS Mac from the command line by doing the following:
launchctl setenv RUNTIME_SELECTOR 1
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