I'm thinking Nextcloud will replace much of it for me

GrapheneOS F-Droid LibreOffice ProtonMail I have been Google-free for 3+ yrs.

Nextcloud will replace all Google setvices?

Gmail: protonmail, tutanova Drive: buy external hdds and backup your shit, syncthing and Nextcloud Photos: see above + immich Maps: MagicEarth, GMaps WV Contacts/Calendar: radicale/nextcloud + davx5 Search: duckduckgo Gboard: openboard Meet: jitsi Docs: libreoffice Notes: Simple Notes Android: Graph...

I've almost completed that quest! Here's what I'm using: Google > Kagi Android > Calyx App store > Fdroid and direct download of apks (just starting to try out Obtainium) Email and calendar > Proton Drive and Docs > combo of Markor and Syncthing for notes, and using Yunohost to host Cryptpad Contac...

A Synology NAS does a great job of replacing the core services. Theoretically even email, although I would recommend against using your own email server for obvious reasons.