Cheating a little - it was in 2019 - but an Essex Acoustic Grand. It's been a bit of a long-time dream come true. If it still has that "new piano smell", does it still count? Our old acoustic upright was falling apart, and it was time for an upgrade. My wife and I walked into a showroom that was a virtual sea of grands, and we converged on the very same piano, so it was meant to be. Now I have to decide for 2021 whether to get fancy piano mics or just get Pianoteq!
Oh, and if we expand the category a bit, this year we got a cute little puppy. We got turned on to a great breeder in the area, and picked her up just before the first lockdown, so she helped us weather the insanity.
Worst purchase was a carry-on fold-up piano. Great concept - a "full-size" 88-key controller that you could stuff into a backpack or carry-on bag - I'd been looking for something like this for my mobile musicality. Three major flaws:
The hinges at the folds don't lock (not a show stopper - still could have been a fun hardware project)
The action is terrible - the black keys are excessively cut down in both the vertical and horizontal directions, and
No touch sensitivity - a total deal-breaker - came as a surprise, since much cheaper keyboards have it - even from the last millennium. So, it was basically just a toy after all.