My 2 cents...
First understand the difference between a bare metal hypervisor (Type 1) and Type 2 hypervisor. Then pick one and work with it (and only it) do not jump around. The problem with Linux etc is that there is too many shiny things to distract you.
Picking a Hypervisor will depend on the resources you have available to you. Personally I use Proxmox to manage my entire lab setup on my own server hosted at home. However before that I used WMware Workstation on my old i7 PC.
Once the Hypervisor is up and running you can then create Linux enviroments and Windows Server setups / SQL whatever. Do not neglect learning about how to setup up Windows Servers, AD , SQL, DC and whatnot. You will have more job oppurtunities for Junior admin position if you include Windows as well as Linux.
Focus on building a strong foundation, Linux, SSH, Python, Windows Server, Powershell etc.
Once the foundation is strong you build from there, into either System Admin / Cybersecurity / Pentesting / Cloud...etc. Quite honestly there is so much variation in the IT space you can literally do anything, provided you have taken the time to build the foundation correctly and are always willing to learn learn learn...
Personally I started off as a RMA consultant at a IT company 20 odd years ago, today I am a Software Solutions Architect. [a role that did not even exist 20 years ago]
Good luck OP..