Is there a way to update my OS (10.10.5), but not all the way to Catalina?

Yes,

The model and year of your Mac will determine which macOS you can upgrade to,

read the following links.

How to upgrade to macOS Mojave - Apple Support

How to upgrade to macOS High Sierra - Apple Support

How to upgrade to OS X El Capitan - Apple Support

Before upgrading make a full back up of your Mac.

Check that third party apps you use have updates available for the new OS.

https://roaringapps.com

Check that your printers/ scanners etc have updated drivers and software available for the new OS.

Connect your mac to your router rather than rely on WiFi,

do not use your mac while it is downloading

and do not use any other devices that share the same internet connection.

I recommend Catalina as it has the latest security updates meant to make your Mac more secure. But, if you run 32-but apps you can download Mojave here: https://itunes.apple.com/us/app/macos-mojave/id1398502828?ls=1&mt=12

Changed your mind? Catalina is here waiting for you: https://itunes.apple.com/us/app/macos-catalina/id1466841314?ls=1&mt=12

want High Sierra? Also an option: https://itunes.apple.com/us/app/macos-high-sierra/id1246284741?ls=1&mt=12

Both High Sierra and Mojave still receive security updates from Apple.