I have tried many times to upgrade the OS on my macbook pro 13" mid 2012 Unibody. Is there a way to install the latest OS that i just don't know about or is this model simply too old.

Hello,

Unfortunately, the hardware of your Mac is too old for macOS Monterey as the earliest model eligible is from 2015.

macOS Monterey is compatible with these computers - Apple Support

The latest available macOS for your model is macOS Catalina.

macOS Catalina is compatible with these computers - Apple Support

I hope this helps.

The Age of this computer will Govern what newer version of macOS it will Qualify to install. Use About this Mac from the Apple Icon on Desktop - the required Information will be there.

With the above information in-hand - follow this How to get old versions of macOS and verify what version this computer Qualifies to install.  For Best results use Safari to commence the download as Others may not work.

Safari will open a redirect and open the Apple Store where the download can commence

macOS Catalina is compatible with these computers This is the Last version of macOS this computer Qualifies to run

Make Time Machine Backup  is very useful and can be used to Revert to Previous Working macOS

Notation - Mojave is the Last version to support 32 bit applications / extensions and Drivers. Catalina, Big Sur & Monterey supports only 64 bit and there is no workaround.

Suggest using Go64 to find 32 bit application before attempting the upGrade. Some or many of the Application already installed may required update or upGrades to 64 Bit Versions.

Are there any AntiVirus, Disk Cleaner, Optimizers, Un-installers, etc installed which should be removed as per Developers Instructions. They are useless, unneeded, cause havoc and interfere with the normal  operation of the OS and may even Corrupt the OS requiring a Reinstallation