I swapped from iPhone to Galaxy S10 a week or so ago (only had the iPhone since January having giving the XS Max a try and selling my previous S9+). Just also had a Galaxy Watch 46mm. I put MFP onto the watch and soon as I did had a mail from Under Armour (owners of MFP) to say that I had been upgraded to Premium on MFP and MMR for 12 months.
Cant seem to see this ‘promotion’ advertised anywhere so wouldn’t be able to confirm what conditions need to be met (There is a chance that the watch is not an EU or UK watch) but if you have a Galaxy watch and android, maybe worth installing MFP to see if you get the same offer.