We went to Playa Blanca Lanzarote in December 2019, it was our last holiday before the pandemic.
We stayed in Villas Puerto Rubicon - the pool isn't heated and we didn't use it, but we did use the garden/BBQ area and also swum in the sea most days. The villa was lovely and a few minutes walk from the beach and marina with restaurants, and also a large convenience store and bakery.
www.villaspuertorubicon.com/
We booked through On the Beach, which I wouldn't recommend (they don't book the flights straight away so you have a nervous few hours in case the price goes up). In future I'd just book direct for the flights. You can book the villa direct or as part of a package with various operators.
Flights, we probably booked 2/3 months in advance because we almost never book more than that far ahead, but that was mid December, not the Christmas period. We have booked as little as a week or two before, mostly using Ryanair or Jet2, sometimes Easyjet, as that's where we have the best choice of flights from Leeds, Liverpool or Manchester in that order of preference. We have quite a lot of flexibility, so will use whoever is cheapest for sensible flight times if possible.
I think if I was to go to the Canaries again between about November and April, I'd look for a heated pool if I thought I would want to use it for swimming, but realistically, we generally sea swim/snorkel/dive more and will then just wear rash/wet/drysuits as needed.