iCloud login issue during Catalina upgrade on older MacBook Pro

Got a MacBook Pro, it's an older model, I'd say early 2010s model, maybe a tad later, and when I got it, I had to reset it from scratch as the previous owner didn't give me their password and such. When I first got it, the laptop had Catalina on it; however, when I reset it, I downloaded Yosemite onto the system. I am trying to get it back onto Catalina, but every time I go through the proper channels, it won't let me log into my iCloud.

I have legitimately tried everything. I have reinstalled Yosemite twice, I have reset my iCloud password and verified that what I typed into the laptop is the same as what is supposed to be correct, and it won't let me log in. I don't have anyone I can borrow a MacBook from to create an install drive, so I am running low on ideas.

[Re-Titled by Moderator]

Original Title: Trying to upgrade a laptop to Catalina, and every time I try to log into my icloud, it says the credentials are wrong regardless of what I do.