For light I don't think it gets much better than a lot of the Golden Age stuff. The distance in time helps to make even gruesome things less dark ;) and a lot of it is very intentionally written as leasure literature to pass the time - which doesn't mean the writers aren't good!
I love Dorothy Sayers. I think Murder Must Advertise is absolutely fantastic, it has such quick dialogue and snappiness. The actual plot is a bit so so and also I don't understand cricket, but this does not matter. But she's always good! I can also recommend her short stories!
I listen to the Shedunnit podcast and was from that introduced to ECR Lorac, who has sort of been rediscovered as an author and thus reprinted. I've only read one but loved it.
I love Ngaio Marsh too, but she's uneven I suppose. If I look at her critically. Read the one where he meets Agatha Troy, Artists in Crime!
Ellis Peters is always a sweet and easy read (not Golden Age, I know). She has such a fundamentally positive view of people, even in her "grittier" books. Every book centers a young and idealistic couple that are so nice and lovely and the hope for the future somehow, which is very relaxing. She also describes nature and localities so prettily and which such warmth. You always feel hopeful after her books.
I've also highly enjoyed Sara Paretsky, Sue Grafton, some of Laurie R King.