I was blown away by how nice Croatia was. Went there in 2003 I think which felt fairly adventurous at the time (wasn’t really but felt a bit different to the big standard week in Spain).
Massively want to go to Dubrovnik.
It's got to be abroad for me - I've had some nice little breaks in the UK, but it's also worth saying they don't perforate the norm enough to stand out as experiences - I'll take a beach holiday or city break abroad over a UK stay any day.
When things eased in September, we rented a house in Abersoch which was lovely, and in 2019 me and friends rented a big house in the lakes as a couple's break, right on the water at Windemere. Both were great breaks which I recommend, but as the OP said, it's not comparable to waking to perfect weather and crystal seas. That transportation away from the norm is what's so great about it all. UK breaks are not far removed enough for me, and represent horrid value for money generally.
I was lucky enough to go away in 2020, to Tallinn and Helsinki over five days in February before things started to change. Tallinn especially was an incredible little city with a great history that I would recommend to anyone - We flew there and back, stayed in a nice four star hotel, ate at good restaurants every night, visited multiple hotels and also caught the ferry across to Helsinki and back and saw the sights there, all for less than £600 as a couple - phenomenal value in my eyes. We ate at the best restaurant in Estonia, 3 courses and wine and it came to less than the equivalent of £40 - expensive for Estonia but compared to the UK, you'd pay probably quadruple for a similar quality over here.
In contrast, 3 nights in Abersoch, when including travel costs to get there, food for the house, eating out a couple times a day (given most of it was spent at the beach which is free) still ran us upwards of £450. I know which I felt provided the more lasting, meaningful experience and was better value for money.