!dev, sort of

So, apparently my Play Store settings get reset when I restart my phone, so Google decided to update Google Keyboard to Gboard for me (and god-fucking-dammit, that shit is absolutely useless to me). I can find older .apks on websites like APKmirror for Google Kinstall but they won't install, saying that "it seems like the package is corrupt". I'm not sure exactly why this might be happening, but according to APKmirror’s FAQ it might have something to do with cryptographic signatures or that a newer version is already installed on the device. Gboard is disabled and I assume that should be enough for that, and I don't know if it would even detect it as the same app in the first place, so my best guess is that it’s got to do with the former which is why I'm turning to you guys.
Does anyone have advice for a solution? I don't have any problems getting another keyboard either if needed, but I would really like something that both has separated layouts per language, as well as a similar swipe-to-type function, since excessive tapping really aggravates my CTS. :/ Any suggestions?