Vaultwarden behind mutual tls and reverse proxy and https://github.com/oguzhane/bitwarden-mobile until https://github.com/bitwarden/mobile/pull/2629 is merged
But honestly all services you mentioned are worthy.
Anything that fits your needs imao
RPI4/400 is perfectly capable as a little home server. All it needs is a good SD card.
Owntracks,photoprism,monocker,brave go m-sync,libre photos,wallabag,radicals e,Baikal,Firefox sync,Joplin web,webdav server,jellyfin,vaultwarden,wireguard
Davx⁵ has Mac OS caldav carddav server integration so you can sync with it.
https://www.davx5.com/tested-with/calendar-and-contacts-server
On android you can use simple calendar or etar to view calendars and "tasks" or jtxboard for tasks/journals
Icard is actuality the only alternative that can register as a contactless nfc payment that not relying on google/Apple wallet and its perfectly safe. It's an actual bank in Bulgaria and is eu regulated and PCI certified
Not Foss. Kinda of a privacy nightmare as you need to verify your identity and location with actual documents but as already said its not google and is a solid option if you are degoogled.
Together with the other suggestions jtx board is also a new addition Developed from the davx5 team , tasks,calendars,journals and NOTES.
The good: Easy sync of notes with any caldav provider . No extra servers and apps for tasks,cakendars,journals. Mtls support ( davx5 supports it ) for extra security if you selfhost
The bad: No desktop client
This probably will never hapen Being a flutter app needs flutter plugins to call the aprpriate android api's This is problematic when it comes to silent instalations
Google bans new acounts that never used in official playstore before
Use a spare gmail acount that you have also used with playstore
Anonymus logins also get rate limits or get banned
As for alternative
App lounge from /e/ OS uses auroraOSS Gstore api to download from playstore so it's basically like using aurora
Other than that the are Python scripts you could use on termux but those also need a proper gmail account
Same apply to linux/windows programs available
I always used my "normal" google account in Aurora also been using this account with microg since ages Never had an issue I don't care if the account gets banned though.
Maybe appkmirror is the only other "sane" option.
You'll still have gms and google apps installed also the proprietary apps installed Most are system apps but some can be uninstalled
Have in mind in stock OS's you'll need an account to recover from a factory reset
Notes:Joplin (over webdav)
File manager:material files
Cloud:webdav provider (webdav mount in material files)
Contacts/calendar:davx5-etar
Sms/call log backup:smsIO
Cast:Bubbleupnp (non Foss)
Browser:mull/brave
Password manager:Bitwarden
Office:proprietary
Themes:Substratum
Maps:here (non Foss)
Gsm location provider:MozillaNLP/MicroG
Speetch to text:localstt
Text to speech:Flite/espeak/rhvoice
Keyboard:Anysoftkeyboard
Network scanner:Ning
Find my device:Nulides Findmydevice
Call recorder:BCR(magisk module)
Weather:Geometric Weather
Parental control:Time limit
RSS:read you
App store:obtainium
Bookmarks:wallabag
2fa:aegis
Location history:traccar/owntracks
Email:tutanota
Image2text:OCR
Translate:deepl
Photos:uhuruphotos/photoprism android gallery/Aves/image toolbox
Appops:app manager
Addblocker:addaway
Files encryption:droidfs
Downloader:download navi
Filesync:folder sync(non Foss/paid but best)
Logs:logcat reader
Launcher:nova(non Foss/paid but best)
Doc scan:open scan
Kernel manager:smart pack
VPN/tunnels:wireguard
Nextcloud is an overkill. Its just too much. I'd say better split down the needed services. Baikal/radicale etc for contacts/calendar. Photoprism/librephotos etc for photos. A webdav server for storage. And so on.
Flash microg if your rom has signature spoofing