I would happily ditch the Windsor / Saxe-Coburg anthem - unsurprisingly perhaps as I am a republican. But it really is an awful, soulless dirge. I'm an atheist too but I find the hymn Jerusalem altogether inspiring.
I too am a 'devout' atheist and having just re-read the lyrics to Jerusalem, they are pure speculation, including the fact that Jesus supposedly visited England.
In my opinion, and I'm not decrying peoples' beliefs, I think, but the words are mumbo jumbo.
How could Jerusalem be built on England's 'green and pleasant land' ?
I know this is nothing to do with Fulham, but as far as Jerusalem is concerned, the actual 'tune'
is magnificent, as is Rule Britannia, but of course we don't "Rule the waves anymore"
Another option would be "Land of Hope and Glory" with tweeks
Note my leaning to the Last Night of the Proms.
It was originally a poem by William Blake, written at the start of the 19thC - he was concerned about the effects of the Industrial Revolution -'These dark, Satanic mills,' and harked back to the legend of Jesus visiting England, as you say.
The idea of 'Jerusalem being built in England's green and pleasant land', though literally unlikely, like Jesus visiting the country, does have the optimistic idea of a far better society being created here, a utopia, and is anthemic, and great to sing, I think- a bit like 'Al Fayed take us back, to a place we call home', which envisages the Cottage as a magical , Utopian sort of place by the historic River Thames - which it is, of course!
You don't have to be religious to like the song -I'm not.
As for Land of Hope and Glory, well it does refer to the, long gone, British Empire, and England as 'Mother of the free,' ruling over all its subjects, and has a bombastic tone and tune, and is usually sung at Last night of the Proms.
I far prefer Jerusalem as an anthem, and it is an unofficial anthem, often sung at sporting events, anyway.