I used Google before, but since I degoogled, I only have my contacts on my Android phone. However, I would like to be able to access them on Linux too and have them synced.
Use a service with card DAV support like posteo.de.
My contacts are synced between an iPhone, Linux Mint and a Mac. My Parter syncs between an iPhone and a Windows PC (Witt Thunderbird as mail Client).
ptz@dubvee.org 7 months ago
I run a Nextcloud server and use DavX5 on my phone to sync my contacts and calendars over WebDAV. Works great.
If Nextcloud is more than you need, you might try Radicale which just does CalDAV and CardDAV.