Also it seems like the amount is of type number. Ideally you would calculate in Dollarcents or Eurocents (I.e. solely use integers) like

100 Eurocents equal 1€

So you do not have any rounding involved

Also if a request comes in twice there are no requestids involved. Therefore it might be possible to generate another transaction it seems.

There are great blog posts from Stripe engineers about these request ids to make requests idempotent with Postgres databases. I highly recommend reading them.