Dear Outstanding Educator,
It won’t be easy.
According to your Twitter profile, your current teaching role is in PE at the high school level so you are starting from scratch with the math education courses needed to obtain a teaching certificate in secondary maths (a requirement for most of the US, not sure of the UK).
Even if additional coursework isn’t required or you can get provisional approval to teach until you do, it’s still a significant amount of content knowledge to master in order to get hired: Algebra 1, Geometry, Algebra 2; you’ll increase your hire-ability if you can also teach Calculus and Statistics.
Have you thought about teaching Physics? It’s an incredibly in demand teaching position in the US and you can teach some Calculus as part of the advanced placement Physics courses.
My two cents, FWIW.