As long as the pipeline is made of steel, nothing can happen. /s

I would say, it’s them caring about the product and their needs, rather than the underlying stack.

I assume you tried using Joplin as a to-do list app? IIRC it worked, but was too fiddly with the square brackets.

Tasks.org is an open-source to-do list app working with multiple providers. On first glance, CalDAV and EteSync might be something for you (ignore DAVx⁵ as it’s a worse CalDAV).

As for me I’m using CalDAV my mail provider mailbox.org is providing me together with Tasks.org on Android and Thunderbird on desktop.

For first few seconds, I deadass though they are talking about Germans with a height of 1,5 meters.

What about boolean though? /s

Do your services need to be reachable from outside right from the start? If not, get yourself comfortable with hosting, maintaning and backing up the server. Automate your backups as much as possible and recover at least once from a full backup to check everything!

This should give you a solid baseline to then think about exposing your services, which is arguably the scariest part, but can come afterwards.

Quad9 does also offer DoT and DoH.

PairDrop is a fork of SnapDrop, which at one point had more features and active development. Don’t know, how it is nowadays though.

Ohne Kliemann zu verteidigen oder gar in Schutz zu nehmen, kann ich dir dennoch seine Folge bei Feelings mit Kurt Krömer aus dem letzten Jahr empfehlen. Dort wirkte er deutlich reflektierter und verständnissvoller, als noch vor paar Jahren auf mich.

I can recommend you ICSx5 for ical subscription and DAVx5 for calendar synchronisation.

Yet I would agree, that a good calendar app should ship with these features.

The German technology blog Kuketz has a comprehensive overview and comparison of all major messenger services.