My findings so far: I had .net and extension conflict, so uninstalled SSIS. Then I tried reinstalling it.
The log file indicates an unstable parent registry key.
Ran sfc /scannow in cmd and resulted in nothing.
Uninstalled Net8 bootstrapper from programs, restarted.
Once that was done, I was able to launch the Visual Studio Installer, add SQL Server Integration Services Projects 2022 back from the extensions list, individual components.
Extension was visible in the launched app Visual Studio Extensions.
Enabled the extension and was prompted to upgrade to ver 1.5. For some reason that was handled as a download.
Completed download and ran that as administrator with repair option because modify options were to install somewhere else or uninstall. That failed.
Followed troubleshooting link: https://learn.microsoft.com/en-us/sql/ssdt/ssis-vs2022-troubleshooting-guide?view=sql-server-ver16#installation-issues, which is where I am now and I'm tired and going to bed.