hard drive – macOS Catalina not allowing me to access full storage on my disc

My hard drive has around 90 GB on it, however Mac is only letting me access/detecting around 40, yet still somehow seeing that there are almost 90 available. I have tried googling around, however most issues seem to be related to the Mac incorrectly calculating the available space but still reading the correct total capacity. Has anyone encountered this issue before? enter image description here