Update:
After posting the above, I took the following steps:
1) Unplugged Time Capsule, waited 30 seconds, plugged it back
2) This time my Time Capsule appeared under Available Disks. I selected it and backed it up.
I was able to successfully back up my files. However, 10GB of new info to be backed took 6 hours for some reason. That's far longer than what is typical from my experience.
After the backup was complete, I was able to see backups going back 4 years, which is the correct timeframe and what I needed.
***************HOWEVER***************
Since that aforementioned backup:
—Time Machine has not backed up my files again despite my computer being next to it and on for days at a time, and despite my Macbook Pro successfully connecting to the internet by way of the network I created on the Time Capsule.
—Time Machine continues to NOT list my Time Capsule as an Available Disk.
—Time Machine DOES list my Time Capsule as a Backup Disk.
—When I click the Time Machine button in the top right menu bar and press Backup Now, it says “Looking for backup disk”. It never finds my Time Capsule.
***************RESPONSE TO BOB'S QUESTIONS***************
Thanks for trying to help out Bob!! Much appreciated!
Here are the answers to your questions:
MacOS Monterey 12.2.1 (downloaded and installed 4 days before I noticed my computer was no longer backing up)
2019 15-inch MacBook Pro
Note: Internet comes from my internet service provider out of my wall directly to the cable modem. It goes via Ethernet to the Time Capsule. I connect my computer wirelessly to the network I created in the Time Capsule. I have not created a wireless network via the cable modem. So again, the computer is “seeing” the Time Capsule in the sense that it is both connecting to it to use the internet, and is seeing the backups on it when I enter Time Machine from a Finder window.
Q. Open AirPort Utility, click on the Time Capsule to select it and then click Edit in the smaller window that appears. Click the Disks tab at the top of the AirPort Utility window to display info about the Time Capsule hard drive.
A. When I open AirPort Utility, I see a circle that says Internet below it, with a green dot to the right. At the bottom of the window I see “No configured AirPort base stations have been found. AirPort Utility will continue searching”. Airport Utility isn’t see the Time Capsule (again, even though I can pull in backups from 4 years ago, as well as connect to the internet)
Q. Click on any Finder window and the Time Capsule should appear on the left panel of the window under the Locations heading. Click on the name of the Time Capsule and another window will open to the right to display "Data" or the name of the Time Capsule hard drive. Double Click on "Data" and wait for the disk icon to appear on the desktop.
A. The Time Capsule is not showing up in the Finder under locations (or anywhere else).
Q. Last question for now.......is the MacBook Pro the only Mac that is backing up to the Time Capsule, or are other Macs also backing up? If other Macs are backing up, any issues?
A. The MacBook Pro is the only computer backing up to the Time Capsule.