If you are on macOS, then you can use the Denon eXtractor Tool (DeXT) to do to job. DeXT is part of the Denon Conversion Utility distribution and is a one time payment, so not subscription based.
Keep in mind that regardless of what conversion you use, analysis of audio files is required in the target DJ software. The analysis creates the preview, overview and WAV graphical representations of the audio file. Sometimes the analysis overwrites the converted values for grid/bpm and key, but in Rekordbox you can turn analysis of those off. You still need to check one box for analysis and I recommend to use phrase analysis for that. If auto-analysis is eneabled in Rekordbox, then you can not disable BPM/grid.