Hedgedoc and Nextcloud Notes

Gitlab isn't really lightweight. It is cool, but not lightweight.

Plus they always try to hide how stuff works behind the scenes so that day that upgrade script has a bug and fails, it’s hard to revert to a working stage.

Yunohost is creating backups for apps that are being updated. If update fails, it automatically reverts. Yes, it works, I checked.

those projects get eventually abandoned,

Yunohost is here for years now, and it does not look like it will be abondoned any time soon.

Nextcloud is hard to install in manual way (even sometimes with Docker). As far I know, both Snap and Yunohost versions of Nextcloud are solid. I used Snap version on the cheapest Linode VPS, and it worked fine, especially when I doubled the SWAP to 1 GB. Now I use Yunohost version and I have only good time with it. It is super stable, fast and reliable. I used Nextcloud_ynh on HP 800 Mini G3 with i5-6500t and now on Asrock Mini PC with Ryzen 7 5700g. It is working just great.

If you don't want to use Nextcloud, you ca install Vikunja for kanban and tasks. For notes Hedgedoc can be great.

Maybe HP 800 Mini with i5-6500t? I had this, and now it is available in Poland for around 500 PLN (~112 EUR). Something like: https://allegro.pl/oferta/hp-800-g2-dm-i5-6500t-8gb-ssd-120gb-w10p-mini-13752172316?fromVariant=13752110554 I had the same model but G3 (different chassis) Power consumption was low. With a 1TB USB HDD connected, power consumption was 7-8 watts.

Yes. I have Orange Pi Zero 2 with 1 GB of RAM running Ubuntu. This is actually very powerful machine, more powerful than my Raspberry Pi 3B+. i bought it for about 180 polish zloty (around 40 euros). I use it for printing server with Ghostscript printer app installed via Snap. I also tried Wireguard and MongoDB - everything works fine. it works really well, but it sits around 50 C on CPU, so it can get hot.

It will not be that great like on Raspberry Pi, but Mini PC are also very low on energy. For example,. Wyse 5070 with J5005 idles around 3-5 W, which is really great. i had HP 800 Mini G3 that idled ~7-8W. Mini PCs are more powerful, expandable and can use normal SSD Drive. For selfhosting they are better, but in some places Raspberry Pi (or alternative like Orange Pi) will be better, especially when you need something small and really low power

I use Nextcloud photos. It is far from perfect but it is OK. I hate lack of good Mobile App.

For PiHole it will be OK, but for Nextcloud or Jellyfin is too slow. It is better to buy used MiniPC/Terminal - it will be more powerful

Wallabag! I am using it for more than a year and it is great

You should be concerned, because there is always a risk, but there is also a risk when you are just using internet even without selfhosting. It is good to remember some rules:

1. Keep apps up to date
2. Open only that ports, that you need (80, 443, maybe 22 for ssh)
3. If you open ssh port, use keys authentication and cut possibility logging with password
4. Do not expose apps, that you are not need in this form, for example Yunohost allows to hide apps behind Yunohost SSO logging page
5. Using cloudflare or/and Fail2Ban is cool
6. Maybe I am a little bit paranoic, but I do not expose apps, that can be used anonymously by everyone, for example link shorters or pastebin alternatives.

It is not all of course.

Nextcloud Deck is a really good choice and I use it, but I also know Vikunja is great