You can export a timeline from Resolve in fcpxml format. That said there is usually some issues with using software to software transfering. I do the reverse all the time. Taking timelines from AVID, Pr and FCPX into Resolve and there are always things lost in translation because of sizing, moves, fonts, plugins or color grades. Not everything can translate. That is normal so going from Resolve to FCPX, the basic edit will come across reliably.