I bought the remaining tier milles when they went on sale. I had a bunch more flights, so that was a facepalm moment.
Then the lockdown went in, got vouchers for everything and I turned out alright.
I did a round-trip athens, jtr-ath-bru and dus-skg-ath-ams this year. I could fly to Stockholm on sas plus flight, but just buying the milles seems easier at this point.