Not Enough Storage to install Ventura

Make sure all of your backups have completely transferred to external media. Many times storage space is tied up into hidden APFS backup snapshots which eventually will be deleted some time after the backups have successfully completed being transferred to external media...this may take a day or even a week and is determined by the backup app and possibly macOS.

Here is an Apple article about APFS snapshots:

View APFS snapshots in Disk Utility on Mac - Apple Support

And another third party article for thinning and deleting APFS snapshots:

https://derflounder.wordpress.com/2018/04/07/reclaiming-drive-space-by-thinning-apple-file-system-snapshot-backups/

It is also possible some of your storage space may be used up by an iPhone or iPad backup if you backup those devices to your Mac. I'm not sure if this would also be considered "Other", but those mobile device backups are hidden on the Mac.

Reboot your Mac which may free up some space. Maybe even boot into Safe Mode which will delete some temp & cache files...then reboot normally. Your web browsers can also utilize a lot of cache storage, so within each browser find the option to clear their cache...may be located under security or privacy options in each browser's setttings/preferences...I have no idea where the option is for Safari. Also make sure you have emptied the Trash.

Make sure to have a good backup before even attempting to upgrade macOS just in case something goes wrong during the upgrade process.

It is generally a good computer practice to always keep at least 15% to 20% of the Total Drive Capacity’s as Empty Space. Allowing the computer to drop below these guidelines may eventually, cause unintended consequences.

The links below will assist in identifying what is taking up space on the Internal Drive and provide possible ways to remove data that is under the direct control of the User ( Home Folder ) . 

Rebuild the Spotlight index on your Mac

What is “Other” storage on a Mac, and how can I clean it out?

Free up storage space on your Mac

OmniDiskSweeper Safe to use

GrandPerspective 

How to delete Time Machine snapshots on your Mac

See used and available storage space on your Mac

Locate backups of your iPhone, iPad, and iPod touch

The final word from Apple on Managing the " Other/ System Data “ Category

Other / System Data: Contains files that don’t fall into the categories listed here. This category primarily includes files and data used by the system, such as log files, caches, VM files, and other runtime system resources. Also included are temporary files, fonts, app support files, and plug-ins. You can't manage the contents of this category. The contents are managed by macOS, and the category varies in size depending on the current state of your Mac.