macOS Catalina 10.15.1 suffers from extremely high application start up time
Your Late 2013 MacBook Pro does indeed have the integrated decryption functionality in hardware. It is not too old for that. It is integrated in your CPU.

So that solves the riddle of whether or not the slow app loading times are related to not having that - it isn't.

You can disable the encryption of the file system "without pains" by opening up System Preferences => Security &amp; Privacy => FileVault and click "Turn Off FileVault..". I'm pretty sure it won't help your application loading times though.

Note that disabling FileVault takes a long time. It runs in the background so you can continue to use the Mac, but it will be slightly less performant during that time.