I'm in my 60's.
Gosh, that recently for the last passenger train ferry. I suppose that was the one from Sassnitz. I thought it had been gone longer than that.
Although I never used it I can remember the hovercraft from Copenhagen Airport to Malmo- before the bridge was built.
I can't remember the name of the ship but there was a wonderful old ferry (when built the largest ferry on the Baltic, but now titchy half a century or more later) which used to do an overnight cruise from Stockholm to the Alands and back - a hugely different experience to the big fancy Viking and Silja boats we have now). She seems to have gone before Covid.
I sadly never got on the Silja Finnjet when it was in icebreaking mode - that was supposed to be quite an experience.
The only really long train trip I've done in Sweden is the Narvik (Norway) to Gallivare then all the way down the Inlandsbahn. I've mainly done ferry hopping, or used to enter Sweden via the Helsingor superflex ferries or the Frederiksaven to Gothenburg ferry then train up to Oslo and onwards. I don't think I've even done the Malmo to Stockholm main line as I've done Stockholm from either Oslo or Gothenburg. I've never flown in to any Scandinavian country- always overland.
My Baltic cruise which took in Bornholm and Gotland was a bit of a cheat, as it was a cruise, rather than getting there on the ferry routes!!
I've done much of the Danish rail network and almost all the Norwegian network, but as I say most of the Swedish network is a mystery to me, as is the whole of the Finland network.