Time references for posts are different because we all live in different time zones. To refer to a previous post, you can reference the post # in the red line above to post, far right end. For example, your first post was #4, then I responded in Post #5, you came back in post #12, etc.
I noted while I was typing in this response that Sly has suggested reformatting the Time Capsule. That is also what I recommend, but here is more information on why that may be your only option at this point.
The error message you posted says the hard drive in the Time Capsule has hardware defects. It's a hardware issue that has no good fix. You can reformat the Time Capsule (losing all of the backups on it in the process) and that may rescue it for a while, but drives that develop hardware issues generally cannot be repaired and they don't heal. Reformatting the drive will mark the failing sectors as not usable, but if others start to go bad as well, the problem will return. Just be aware of that reality
Apple has also, with Catalina, renamed the backups from sparsebundles to backupbundle, so the file with that name is probably the most recent Catalina backup. You might see if you can get First Aid to run on that backupbundle by again double clicking to mount it and see if it can be read properly. The two sparsebundles are from your old desktop and from your laptop from before you installed Catalina. I don't know if you have anything in the before-Catalina backup that you might want to recover at some time, but wanted you to know what they are.
If the backupbundle mounts to your machine and if First Aid reports no errors on the backupbundle image, you can try to copy the file from the Time Capsule to a different external drive. Here is Apple direction on how to do that:
https://support.apple.com/en-us/HT202380
Just so you know, because these bundle files are compressed to reduce network traffic, usually any failure of integrity of a backupbundle makes the entire bundle basically unusable, so there may not any way to recover the backup to a different drive and try to recover those old files if First Aid reports errors. You can always try, of course, but don't be surprised if the hardware error gets involved. You can get lucky and the hardware issues be uninvolved with that particular backup, of course.
Do you use the Time Capsule as your WiFi router as well? Apple no longer makes Time Capsules, so finding a replacement may be an adventure. But good Wifi Routers work well and drives are getting fairly cheap, so the option of retiring the TC and replacing it with a WiFi router and an external drive is the way to go, if the drive in the TC fails.