This computer qualifies for anything from Catalina macOS 15 to Big Sur macOS 11 and Monterey macOS 12
With each newer version of macOS, comes more Overhead as in CPU Power, Memory and Space.
Catalina would be the next step up and is sill getting Security Updates, at least until Ventura mcOS 13 is released
Big Sur has additional Overhead from Big Sur but will offer a long time for Security Updates
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.
Computer Qualify for the Monterey upgrade
macOS Big Sur 11 hardware requirements
macOS Catalina 10.15 hardware requirements
Tips Big Sir Upgrade Released Nov 2020
Tips Monterey Upgrade Released Oct 25, 2021
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 require an update or upGrades to 64 Bit Version
