God the level of self pitying nonsense here is astonishing.
The number of people whose knowledge of Eurovision extends to whatever humorous clips make the news or clip shows who pronounce 'knowledgably' about the dynamics of the competition is crazy.
So no, this won't do poorly because there isn't much of a 'gimmick' - Netherlands 2019 didn't have a gimmick. In fact, the only gimmick in a winning entry I can think of in the last ten years was Israel in 2018.
It won't do poorly because the UK is unpopular due to Brexit, Iraq or any other policy - Israel is (rightly, IMO) highly criticised for its treatment of the Palestinians and won in 2018.
It won't do poorly because the UK has fewer neighbours - Israel in 2018, Portugal in 2017 won with the same number or (or fewer) neighbours than the UK.
It won't do poorly because it's not some upbeat europop number. Of the last ten winners, there are maybe two that could be described as upbeat and Europop.
But it might do poorly because of the UK's track record of treating the competition with pretty low respect and putting very little effort into choosing and promoting its entries. Many recent winners have tried extremely hard with excellent entries over the last few years - France has massively upped its game and came close last year; Italy has been on form since it rejoined the competition ten years ago but only won last year. It takes countries (often at least) a few consistent years of putting the effort in to do really well.
It might do poorly because the BBC stage it badly. The staging of last year's entry with the awful giant trumpets was just so outdated and spoke to the sort of old fashioned out of touch views of the competition on display on this thread.
FWIW, I think it's a cracker of a song, and think if its staged well and if his vocals are as strong live as they seem, it will be in the top 10.