Matrix messaging apps. It's nice to have modern messaging features, end-to-end encrypted, with no single point of failure, no Google involvement, and no phone numbers. I expect to start recommending it widely when the 2.0 features land in the popular clients.
WireGuard VPN. It's fast, even on low-power devices.
Self-hosted Mumble. Excellent low-latency voice quality for chatting or gaming with friends.
Radicale, DAVx⁵, and Thunderbird, for calendar and contact sync between mobile and desktop, without handing the data over to Google or anyone else.
Maybe one of these?
https://system76.com/desktops/
https://www.dell.com/en-us/search/linux
https://www.tuxedocomputers.com/