I want my Studio 2019 licence back

I updated to Studio 2019 Plus to Studio 2021 Plus. Studio 2021 works, however, with some flaws which are described in the community section. When checking my licences, the licence for Studio 2019 Plus was gone, other legacies showed though. I need the Studio 2019 Plus licence back for some reasons, but keep on using the Studio Studio 2021 Plus CAT mainly. The exe file for Studion 2019 Plus is still available but it needs the key. Please reactivate the Studion 2019 Plus key.