Authentication failed when pushing on Github Desktop

Hi all, I’ve been using Github + Github Desktop at a super basic level for the past few months — basically only creating repos, committing to main, and pushing updates. That’s been sufficient for my purposes, but a few days ago after “Committing to main” I tried to “Push origin” on a repo, and instead received an error message, saying:

Afterwards, I turned off my firewall and flailed down various online rabbit holes, but to no avail. At one point I followed the advice of this webpage in Terminal: https://gist.github.com/taoyuan/bfa3ff87e4b5611b5cbe
(which btw I now cannot figure out how to undo: when I enter in “git config --global --edit” in Terminal, the popup window contains these lines which I can’t seem to get rid of:

[url "git@github.com:"]
        insteadOf = https://github.com/
[url "https:github.com/"]
        insteadOf = git@github.com:
[url "git://"]
        insteadOf = https://

)

Doing this seemed to turn my error message when pushing into the more standard “Authentication failed. Some common reasons include …” message. I tried to troubleshoot all of the “common reasons” listed (I don’t use SSH authentication), but still no go. I then tried this method: https://www.notion.so/Github-desktop-authentication-error-0fd5bfa1bd85403e9d88f644a9eaf0f7 and successfully added a new SSH key to my Github account, but still no dice! The authentication failed error message is popping up for all of my repos. I made a new repo just to test things out and I can’t “publish branch” either because I get the same error message when I try.

At this point I fear that I have already made things worse for myself by misapplying online advice to my situation, so I’m putting out this SOS here before I try anything else stupid. Does anyone have any idea of what could be going wrong here?