Uninstall the memory app by following the developer's instructions. There is no need for such an app.
macOS utilizes memory differently than it did years ago. These days macOS will keep memory filled all the time because unused memory is wasted memory.
To know if you are running low on memory, you need to observe the memory pressure gauge in the "Memory" tab of Activity Monitor. If the graph is showing yellow or red, then it indicates your workload is causing the system to run low on memory. If the graph is green, then check to see the values for "Swap" and "Compressed".....if either one is using lots of GBs of either, then that also indicates your workload requires more memory.
Since you cannot add more memory, your only option would be to quit an app, or two, or more. You can try rebooting the computer since that can clear out some memory when you restart, just make sure to uncheck "Reopen windows when logging in" so that the system will release the memory for the apps you left running when rebooting. Apps need to be completely closed & relaunched once in a while, plus even macOS needs to be rebooted once in a while.
If the battery is draining too quickly, then it is either due to the computer working too hard most likely due to third party apps which are interfering with the normal operation of macOS, or the battery is wearing out or even failing, or possibly from externally connected devices which are being powered by the laptop.
Option-click the battery icon on the menu bar to see the battery condition (the condition will only show up if there is a problem where it will say "Service Recommended").
To look for possible software issues, run the third party app EtreCheck and post the report here so we can examine it for clues. The usual culprits are anti-virus apps, cleaning/optimizer apps, and third party security software since they all interfere with the normal operation of macOS. None of these types of apps are needed on a Mac and usually causes more problems than they solve. If you have those types of apps installed, then uninstall them by following the developer's instructions.
