I'd say include Windirstat (Portable) in your list of useful tools. Just know what can safely be cleaned and use it more as a reference.
Also, every time I've worked at help desks I've ended up writing my own software for the team. Little apps to do basic things I do every call and attempt to automate my life and call even a bit more. A window that had a line to put the computer name in, auto-ping it, check immediately for certain services, kill Outlook.exe/Skype.exe/Teams.exe at the same time (for OST issues), reboot, etc. Things like that. Little bat files/powershell files/or .net apps.
I found it handy as well when setting it up for changing a users password. I set up a program to give me the user's name (so I could confirm it), check if the account was locked/unlocked, and showed when it was last reset. That way I didn't reset the wrong person or reset when it was just reset that day.
This way you also stay on top of powershell commands (if you use it where you are), and you can personally identify things you do often and start cutting away until your calls are super streamlined. You don't need to be an expert, just identify a need you see often and then start researching how to fix it. It will make you a stronger tech overall and help lead a way off the help desk.