all .net core runtimes install side by side. your project file file specifies the runtime to use. so installing .net 8 should not be an issue.
not sure why you use such an old version of visual studio, but I believe it supports .net 8, but not Maui 8.
The Maui 8 workload install should install .net 8, but it is safe to install .net sdk first. while sdk installs are stable, there have been issues with workload installs due to the number of dependencies. at this point I believe Maui 8 and aspire are stable.
note: Maui 7 is no longer supported. Don't believe you can sign IOS code with it.