Everything you want is definitely possible for the budget.
I used an old I5 laptop with 4GB of RAM for a year or two. If you need a lot of storage, an old HDD will be fine usually. A raspberry pi 4 or 5 will be slower, but would still work, but if Norway prices are anything like belgium, an old I7 laptop sips power and will save money in electric costs
A few tips:
Run nextcloud all-in-one or spend some time optimizing nextcloud. It will help performance a lot
Unless you are a serious photographer, use Immich, 100%. Immich is a google photos replacement that has a bunch of good user features like accounts and good security and sharing that photoprism just doesn’t. Photoprism is really geared towards professional photographers.
transmission + wireguard container for a VPN is the way to go …
radarr/sonarr/lidarr & prowlarr are good to use with transmission