Is there an app to restrict charging to 80% on older macbooks?

My M3 MBA of course has the battery optimizer function, but my 2013 MBA/Mojave of course doesn't. I keep that old workhorse plugged in 24/7 because it does grid computing (BOINC -- World Community Grid, etc.), and that's all it does; and it really requires a small amount of the computer's capabilities. I just installed a new battery (it's 3rd...or maybe 4th?) and I'd like to preserve as much of it as I can, but I haven't found any way to do that, at least as far as apps go. I've not seen any that work for OS older than Big Sur. And I can't do code; somebody has to give it to me to c&p in Terminal or something.

I've seen conflicting opinions about whether the battery saver functions make much of a difference anyway, but then conflicting opinions about battery health and preservation has always been a staple of community battery discussions. Maybe it would be easier to just keep replacing batteries? Though my big fingers have a real hard time with those tiny screws.

So...any insights, links, suggestions would be great. Thanks all.