Am I resetting my MacBook correctly?

Here is the procedure I follow:

Install El Capitan or Later from Scratch

If possible, back up your files.

1. Restart the computer. Immediately, at or before the chime, hold down the Command and R keys until the Apple logo and progress bar appear. Wait until the Utility Menu appears.
2. Select Disk Utility from the Utility Menu and click on the Continue button.
3. When Disk Utility loads select the target drive (out-dented entry w/type and size info) from the Device list.
4. Click on the Erase button in Disk Utility's toolbar. A panel will drop down.
5. Set the partition scheme to GUID.
6. Set the Format type to APFS (SSDs only) or Mac OS Extended (Journaled.)
7. Click on the Apply button, then wait for the Done button to activate and click on it.
8. Quit Disk Utility and return to the Utility Menu.
9. Select Install OS X and click on the Continue button.

There are many ways. From what you described, you did exactly what I posted earlier. If everything is working, then stop worrying about. You're in good shape!! Happy computing.

Any time.

Volume Groups is something unique to Catalina and APFS because APFS and Catalina create five logical volumes on the physical drive. These volumes are all configured in one Container. Catalina creates two of the volumes, the startup volume and its invisible partner - the Data volume. An example: Macintosh HD and Macintosh HD - Data. The other three invisible volumes are used by APFS. They consist of the Preboot, Recovery, and VM volumes.

When you erase the drive to perform an Erase and Install, you must remove the two volumes created by Disk Utility in Catalina. They are what is meant by the Volume Group.

I hope I made this clear. It can be a bit confusing.

Yes. That will display both volumes within each Container in Disk Utility. You can select the Macintosh HD, for example, and CTRL- or RIGHT-click then select Delete APFS volume. You are then asked if you wish to delete the Volume Group. If you answer, "Yes", then both volumes will be removed. I do something slightly different in the procedure I posted. I select the drive's physical entry, what you called "Apple SSD followed by a bunch of numbers." I then click on the Erase button in Disk Utility's toolbar. This creates a newly formatted drive with a single Container and one logical volume. Installing Catalina to that target volume will automatically create the needed Data volume.