https://github.com/deku-messaging/Deku-SMS-Android

Supports emoji & images Supports e2ee if the other party also have deny SMS installed Supports message forwording

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

https://github.com/photoprism/photoprism

And

https://github.com/LibrePhotos/librephotos

With

https://github.com/Radiokot/photoprism-android-client

And

https://github.com/savvasdalkitsis/uhuruphotos-android

Android clients

Your options in aftermarket OS fall in to 3 categories imao

1. those that support relocking the bootloader (grapheme,calyx,divest, other smaller projects maybe)

2. vanilla roms with signature spoofing permission so that you can have microg on them. Some even come with microg preinstalled (/e/,lode,Los4mg) And some are gmscomat compatible (voltage,awaken,spark). There are plenty but they don't care about signed images and relocking.

3. some unofficial build from any of the above from a maintainer that cares to sign his own images so that you can relock your BL as your device supports it.

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.