This is not true, Storeman 0.0.18 from the Storeman-legacy page at OpenRepos works fine (tested on SailfishOS 2.2.1) when the CA certificates are updated and the OpenSSL 1.1.1+1.0.2 combi package is installed.
Wow, thank you! I tried Storeman 0.1.8 before (unsuccessfully), but I had no idea I can make it work on SFOS 2.2. Thank you for help! 