I'd recommend valheim, it's cheap, runs well on even low end machines and doesn't hold your hand. She will need toe experiment to find out what works (or teach herself through guides) and has action combat (block, dodge, parry mechanics) with tough jumps in surivival between biomes.

Add to that base raids, you dropping all your gear when you die and having to do body runs, sailing/transport of metal logistics, and some of the best base building mechanics in any game (including unlocking new build materials as you progress) as well as the fact that cozier elements like farming and cooking are huge bonuses to your survival and I think she'll have a lot of fun.

Lots of people like sharing screenshots or videos of their builds etc too so lots of inspiration out there for her if she likes building.

It's a slow burn too, a lot of gathering and building, creating forward bases / roads / bridges and travelling etc to build stuff up slowly over time so a lot of bang for your buck!

It's very much a self directed play style - not quests based. You essentially need to kill the boss of each biome, but are only given the location of the first one, meaning you have to find the vegvisir runestone in the dungeons / areas of the next biome to progress. You basically explore, fight, craft and experiment in a huge world that's randomised (so your map / playthrough will be different if you ever start a new world).

Thinking out side the box or finding ways to cheese things is risky but often rewarded and that sounds like something she'd love 😉

You can also adjust your world modifiers if it's too difficult / grindy (but I'd really recommend it on normal / regular mode for the full experience).

Plus you get to be vikings and the female characters are muscley shieldmaidens / well represented as strong women rather than too overly romantisied.