I've been using Gmail and iOS contacts for years, and they are supposed to synch; but neither has worked very well for me, except when I use the Google Contacts on my Debian PC or laptop.
I am looking at Contacts+ as a possible solution. Has anyone had any good experience with it, or do you have a better solution to recommend? Note I spend most of my computer time via the Termius iOS app to my local and remote Debian servers and usually have an iPhone readily available. Thanks for any help you can provide. Best regards, -Tom