how to sync iPhone notes with iMac without iCloud

Tester48 wrote:

How to sync iPhone notes with iMac without iCloud

Notes can be stored on a mail server, by setting up an account on the (shared) mail server.

Add or remove accounts in Notes on iPhone - Apple Support

Past that, you’ll want to find a different sync service that isn’t iCloud, and quite possibly find a different app for your notes. Preferably one with the necessary not-iCloud sync services integrated.

I think iCloud is the mechanism for synchronizing Notes.

There is Finder/iTunes synchronization, but it's not as convenient, and it seems to cover Contact and Calendars, but not Notes.

Sync content between your Mac and iPhone, iPad, or iPod touch - Apple Support

Your notes are connected to your email account, see if your email browser allows you access to your notes.

Why would you not want to use iCloud? It's designed for just what you want.