Advice for upgrading my girlfriend’s first gravel bike

So I got my girlfriend a second hand Voodoo Limba for Christmas. It's a solid bike and it's gotten her started into gravel biking with me. I'm just looking for some advice on some upgrades I was thinking about and some recommendations on parts we could use.

Firstly, I'd love to get a carbon fork for it. It currently has a steel fork which is stupid heavy, but I can't find any specific specifications online for sizing a new one. Any ideas?

Secondly, I'm thinking of converting it to a 1x groupset. It's currently got Claris 2×8. Should I look into getting a new groupset or would it be sufficient to simply remove the front large chainring and derailleur. I feel like it's a little bit under geared for some of the climbing we'll be doing, so I'm thinking upgrading to a 1×10 or 1×11 down the line would be good.

Last thing is she finds the cranks are a bit too long for her. I was looking up Claris 160/165mm crank arms and posts about swapping from 170-160 but the links to the actual parts were all old and didn't resolve to anywhere on the shimano site. Anyone here swapped out the crank arms for shorter ones on Claris?

I'm willing to put around 300/400 euro into the bike as a rough estimate.

Any help/advice is greatly appreciated, thanks!