Deleting a "Legacy Extension" did not work, but did I disable it?

Several years ago, my Mac warned me that an app (LeapFrog Connect for LeapPen) would not be usable on the new iOS and that the developer needed to update it. My children weren't using the app anymore, so I uninstalled it. The new iOS update came out, and I started getting a message upon start up that "Legacy Extension Software: The existing software on your system loaded a legacy system extension by LeapFrog, which will be incompatible with a future version of macOS.” I searched for how to remove it, and a BUNCH of responses from this community said things like, "oh, Apple will work out those bugs later; just wait and it will go away."

It never went away. Every time I turned on or restarted my computer, I would receive this message.

Yesterday, I updated to Sequoia 15.4. It appeared to restart just fine; my desktop was up and my widgets were loaded. But then it spontaneously restarted itself, and got stuck in a restart loop two more times before I forced it to shut down and started it in recovery mode. I ran first aid on the drive, in case something went wrong with the update, and restarted it again. The Legacy Extension message appeared, and I realized I had not seen it when my computer restarted after the update. I thought that maybe something had gone wrong in whatever command executed that search-and-report, so I determined that I should get rid of the extension once and for all.

I found a tutorial online that said how to find the extension, through system information. It wasn't one, but two .kext files. Putting them in the trash didn't work (nothing happened). Opening terminal and telling it to remove it didn't work; Terminal said that the file wasn't where I said it was, even though I was looking right at it, and even dragged the file into the Terminal. The command "rm -rf" returned back an error that it was an illegal operation, but I couldn't find anything online that told me why or how to correct it. (I was logged in as Admin during all this).

I found another tutorial online that said to restart the computer in recovery mode, access the terminal from there, and then execute the command. I did. The terminal no longer gave me any error messages, but also did not give me a positive response back. It simply returned to the command line. Web searches said that sometimes that could happen; not all commands execute with a response back that it happened.

I restarted the computer. I did not have the Legacy Extension Software message. But, when I returned to the Library/StagedExtensions/Library/Extensions folder, the two .kext files remained. They were not deleted.

At this point, I don't really care if they stay. I've worked on this for over a day. I'm not a programmer or a computer person in general. This is not a comfortable, or natural project for me and just highlights how little I know about all of this.

But, I don't want my computer to keep "reaching" for it. I don't want it slowing my computer down, I don't want it to create problems in the future, I don't want to have to think about it any more.

So, did I AT LEAST disable the extensions so that, effectively, these don't exist anymore for my Mac?

If I DIDN'T, would someone please walk me through how to do so?

Edit: thank you! Sorry; I'm incredibly frustrated, and I forgot my manners. I really do thank you for reading and helping if you can!