Excel speed - opening files / exiting

Hi All,
using Microsoft Excel on Windows 11. Typically working with CSVs.
Having a problem with Excel being slow to open a file, usually only when I already have a file open.
Opening the first file is no problem, but once I have a file open, any subsequent files take longer than they would otherwise take, to open.
Also, when I close an Excel file, it will often take several seconds to be able to access the file again. Meaning if I right-click the file the list of options including "Open with" etc. Does not show up for a few seconds.
Is it possible this is due to Excel closing but still having some process that is using the file for a short period of time afterwards?
I do have a few macros written and saved to Personal Workbook so I have available at all times. Wondering if this could be the issue.

thank you
Dave

Or it might be the size of those files.

Size of file doesn't seem to matter. I'm not dealing with huge files.
Only variable seems to be whether excel is already open.