Your MacBook runs macOS 11.
Money Manager EX can run with macOS 10.9 onwards, so you should have no problems. (A 512 GB SSD, on any machine, is more than adequate for anything at all, other than for users who, say, want to store vast numbers of large video files locally).
The download link at
https://www.moneymanagerex.org/download might not work properly for you, as it seems to go to a SourceForge page that doesn't load properly. If that's the case, just click on 'Problems Downloading' to start the download.