I think the flights I saw were KLM.
I was suggesting that you use miles to fly roundtrip from Doha to Frankfurt.
Then book seperately a trip from Frankfurt to Amsterdam. Either by plane or train.
That would allow you to use your miles for the most expensive part of the flight. You would only pay for the flights between Frankfurt and Amsterdam, which should be cheaper.
Just be careful with scheduling. Make sure you have time to connect and get to your flight to Amsterdam.