As I know, if you don't need to meet the MTD requirements, you can stick with QB Desktop to save costs. Otherwise, converting data to QBO UK version or other accounting application is unavoidable.

https://quickbooks.grsm.io/UK

You can use MMB services to convert your data, but you should know the limitations. If you need to convert data with additional requirements (eg multicurrency, attachments), you should consider purchasing another conversion service.

https://movemybooks.co.uk/move-to-quickbooks/limitations-of-service-quickbooks/