Debug is not working in ASPNET 7.0.100-preview7 when dotnet 6 is installed

I can run dotnet watch and I can Run my ASP.NET core application, but if I try debugging, I get the error message below. I have .NET 7 sdk installed (otherwise dotnet watch and Run in my app wouldn't work either)

/home/timmy/Repos/myaspnetapp/src/Application/bin/Debug/net7.0/Application 
You must install or update .NET to run this application.

App: /home/timmy/Repos/myaspnetapp/src/Application/bin/Debug/net7.0/BlazorDebugProxy/BrowserDebugHost.dll
Architecture: x64
Framework: 'Microsoft.AspNetCore.App', version '7.0.0-preview.5.22303.8' (x64)
.NET location: /usr/lib/dotnet/dotnet6-6.0.108/

The following frameworks were found:
  6.0.8 at [/usr/lib/dotnet/dotnet6-6.0.108/shared/Microsoft.AspNetCore.App]

Learn about framework resolution:
https://aka.ms/dotnet/app-launch-failed

More info

• I am running this on Ubuntu 22.04 and Rider 2022.2.1, but it seems VS Code has the same issue so I think it's a dotnet issue.
• I have dotnet6 installed in /usr/lib/dotnet, subfolder dotnet6-6.0.108
• I've had dotnet7 in multiple different folders to see if that would make any difference
• In Rider the Toolset and Build path for .NET CLI executable path is /usr/lib/dotnet/dotnet7-7.0.100/dotnet and the MSBuild path is that same folder but sdk subdirectory

It's worth noting that debugging a .NET 7 console project works fine, but not ASP.NET core.

I may uninstall .NET 6 to see if that would help but my hopes are a bit low after wasting hours trying to get this to work. Any help would be appreciated.