Any pilot job is highly competitive and for UK military roles the percentage of candidates accepted for training against total applicants has always been outrageously small eg 1% or less. The majority will be filtered out early doors but even getting through to OASC you would have to be a really outstanding candidate to get the nod. Then the hard work begins. I would always advise anyone interested in a pilot career to have a Plan B, C and D
However, if you’re not in you can’t win.