As you live in Germany, you can buy all Spanish seat reservations at a DB ticket counter (works for many countries). See : https://community.eurail.com/train-connections-reservations-47/how-to-get-reservations-105/index2.html?postid=18419#post18419
If you travel without a seat reservation they will surely fine you.
Just to add, called them and there are 200 open seats for this train tomorrow, so space is not an issue.
You can also book reservations via DB in Germany, at a DB ticket office or by phone (and collect at a DB ticket machine).
You didn't mention a date or departure time but it looks like you're aiming at the 20:25 train from Málaga to Granada (you'll first need to take a suburban train from the airport to Málaga Maria Zambrano). That's an Avant train and reservation should be €4. The normal fare is €23,10, so if you have a flexipass, check if it's worth using a travel day for.
I once overlooked that a regional train had mandatory reservations. The ticket inspector then sold a “reservation” (without seat number) on board, for the same price as at the ticket office.
DB Hotline is not staffed at the moment as all staff is dealing with train strike related issues and I am not near a train station at the moment. Train travel is supposed to be easy and fun but it’s just a pain if things work like that.
Exactly I am planning to take the 20:25 train Malaga to Granada, I do have a 2 month pass so travel days are not an issue. Will I be physically able to get into the train or are there any checks beforehand?
DB Hotline is not staffed at the moment as all staff is dealing with train strike related issues and I am not near a train station at the moment. Train travel is supposed to be easy and fun but it’s just a pain if things work like that.
Unfortunately, Renfe are a pain. The journeys themselves are great, but they decide what passengers have to want. E.g. they stopped the possibility to book pass reservations online.
Exactly I am planning to take the 20:25 train Malaga to Granada, I do have a 2 month pass so travel days are not an issue. Will I be physically able to get into the train or are there any checks beforehand?
I don't know that station yet.
Just to give an update, maybe it helps others. I was lucky that I was able to purchase the seat in Malaga station 5 min prior to departure. No chance to get it on the trains without a reservation as they scan the tickets when entering the platform. Probably it works like that in all major stations. They already check the railpass at the reservation counter and you will get a paper ticket which is basically the ticket then you have to show. If the ticket counter is already closed or even if it is open unofficially you are out of luck. In Granada I wanted to book the seat for Madrid after I arrived at 21:55, the ticket counter was still open but a very unfriendly guy refused to help me with the reservation and told me to come back next day. Somehow also pickup at the machines did not work, I found my seat reservation which I made via phone but the machine would always want to charge the full fare. After that my reservation expired and I had to get a new one.
But somehow I was able to get a reservation on a train which showed as fully booked when I checked online, so I was very lucky.
