Q/- Would steam store region be changed like this

I don't think you need local ID, I believe to change region you just need a payment method in the region. If you have a German bank account you should be fine, and assuming you still have a Moldovan account, you should be able to change back in 3 months.

Well, maybe you shouldn't take my word for it :D

Ideally, someone who has experienced it personally can confirm if it will be a problem for you to set Moldova as your store region while you are located in Germany. I'm not really sure about that part.

To my knowledge nationality is unimportant. What matters is your country of primary residence. In your case I wouldn't change my store location to Germany for redeeming a key. German Steam store is heavily censored and although I'm too lazy to look it up Moldova will have lower prices due to economic reasons.

Support can't and won't do anything about your region settings. Only you can change it and you need two things to do so:

1. The IP belonging to a country
2. A by Steam accepted payment option located in the same country as 1).

Your passport or ID card are irrelevant.

Since you don't want to wait 3 months and also don't want to have German steam store (both relatable), I recommend to find someone to trade: your German key vs. one working in Moldava. Since you mentioned 60 bucks, I assume it's a popular AAA title. If it doesn't work 1:1, you could still try to trade for something equivalent (PayPal, TF2 keys).
Be aware that trading isn't allowed on Steamgifts, so you need to use SteamTrades, barter or other communities.

If you bought it from HB or Fanatical I personally had some luck getting my key exchanged after explaining the situation to them (although mine was slightly different because I got a different version of a game because I bought it from Germany even tho my account and payment method weren't). You might have to insist a little but might we worth a try talking to their support.