Very slow sync to 256gb android sd card

[BobZ1]

Using latest version MMW and MMA. Just rebuilt my MMW library (144gb) and wanted to sync to my phone 256gb sd card. Tried USB sync but MMW told me there wasn't enough space. So deleted music from sd card and re-tried sync. This seemed to work but had slowed down to speed that would take 5-6 days (I thought). Needed my phone so stopped sync, removed sd card, inserted sd card into computer, deleted music files, and started new sync. Initially very fast but after 8800 files has slowed down to 103kb/sec. to sync all 24000 files this could take 11 days. How can I speed up this process? Initially I transferred files using explorer but after reading through forum understood that MMW wouldn't sync unless it had insdtalled the files. So, now using MMW I'm stuck with another 11 days for MMW to sync the SD card. Any suggestions to speed up the process would be appreciated?

[BobZ1]

Gave up on MMW. Cleared the SD card, launched Musicbee, synced the card in 4 and a half hours. so much easier to use.

thanks