perhaps I do not under stand you correctly, what is missing? If you mean php 7.4 than take into consider to upgrade to Plesk Obsidian. In Plesk Obsidian php 7.4 is allready available.
at your screenshot it is the component section - here you will see always only the major version
go to Plesk Panel > Tools & Settings > Php settings and tell us which php 7.3 version you see and check your update settings, php updates comes with system updates
which OS and Plesk Version including MU Level do you have? seems your system wasnt updated for a longer periode of time
and check your settings in Plesk Panel > Tools & Settings > Update & Upgrade settings > General