Problems with importing a site

When I updated from “classic” Local by Flywheel to Local 5.3.1 my original site was corrupted. So I tried to import the site from a backup created from Local by Flywheel into the new Local. I get an error in creating the database. So I removed both versions of Local (old and new) and tired to do a clean install of the classic Local by Flywheel. It will not install anymore.

The best solution is to be able to import the site from the backup (made by Local by Flywheel) as a new site on Local 5.3.1. Is there a fix in the works to be able to do this? What are my options?

I cannot get localbyFlywheel to to work so I have been trying new downloads. In the installation it always says: installation unsuccessful. The icon does appear but nothing past that. What is wrong?