how to show all boot options and then hide them from rEFInd?
If you have the current version of rEFInd installed, then you should be able to hide the undesired menu items by highlighting the icon and pressing the - key. This assumes hidden_tags appears as a showtools option parameter in the refind.conf file. See Hiding and Displaying EFI Boot Loaders for more information.
If you have Hidden Tags enabled, then the following icon will appear on the tools line of rEFInd.

The default location for a rEFInd installation is the EFI/refind folder in the hidden EFI volume (disk0s1). You can mount this volume by using the command given below.
sudo diskutil mount disk0s1

You can unmount by using the command given below.
diskutil unmount disk0s1


Note: You mention rEFIt  in your question. You should not be using rEFIt with Catalina. The rEFIt Project is depreciated and has been replaced with rEFInd.