Suggestions for Italian honeymoon in March?

My hubby and I are finally planning our delayed 2-3 week honeymoon to Italy in March and I'd love to hear any ideas or suggestions. We're hoping for a bit of relaxation, but still want to get out and see some sights. We tend to be good walking and it's always nice to be in a beautiful garden/field, but qe aren't really into super adventurous outdoorsy stuff like hiking and ziplining. Museums are okay (especially when we went to do something indoors) but we much prefer being immersed in the history like with old buildings and such. When it comes to hotels though, safe, clean, and a bit nicer is ideal. We also really like board games and nerdy stuff. We aren't big on alcohol though so wine tastings aren't our thing. And of course we want to be as safe as possible with covid, so avoiding large crowds especially indoors is preferred.

We want to keep the cost down obviously, but we have agreed to one "splurge" day, so maybe 1 night at a really fancy hotel/spa or a more expensive unique experience, so I'm open to those types of suggestions as well. Or anything to avoid?

Thanks in advance!