Here is what I did. I bought an IBM ThinkServer and put as much ram as I could in it (32GB; keep in mind this was 2015). Then I loaded it up Windows Server by itself and played with the Windows and its features. Then I loaded Hyper-V to play with virtualization and created my first domain environment, learning DNS, DHCP, GPOs, an Exchange Server, and VPNs. I ended up throwing a 4-port NIC in there and set up pfsense on a VM to act as my firewall router so I could learn VLANs, traffic shaping, and security. Then I put ESXi on there and learned vSphere and vCenter. You can sign up for an NFR key from Veeam and play with backing up a virtual infrastructure.

There is so much you can do. I started out on Helpdesk in 2015 and now I am a Senior System Engineer that works with the VMware platform all day. If you invest in yourself, it will directly invest in your future and how quickly the promotions happen, and the amount that the responsibilities increase. Feel free to reach out and DM me if you have any other questions that I could help with. Good luck to you!