Many countries around the world, apply a financial year starting 1 January and ending 31 December, matching their calendar year; while the UK financial year runs from 6 April to 5 April.
Both financial years are of the same length, so, there is no conversion required.
Simply take the income arising in the period 1 January 2022 to 31 December 2022 (converted into pounds sterling) and declare it in the 2022 to 2023 UK tax return, as all entries in a UK tax return are in pounds sterling.
The official exchange rates can be found here:
Exchange rates from HMRC in CSV and XML format