I have different problem. Fast reading RP->PC (70-100) and slow writing PC->RP (8-20) by Samba. Results are the same with ntfs and ext4. There is Windows 10 on PC. Writing from 2 different SSD on PC sometimes can give a little faster speed (30-40) for a small moment.
Reading from RP with WD20EZRX
Reading from RP with WD40PURZ (NTFS) gaves 80-100.
USB 3 cardreader (microsd 128gb u1 Samsung evo) in second usb 3 port has same problem.
RP 4 4gb + original PU + cooling + 2020-08-20-raspios-buster-arm64 + clean OMV (wo torrents, dockers and other)
microsd 32gb class 10 u1
WD 2 or 4 tb 3.5 + ugreen SATA3-> USB 3 with external power unit
Same HDDs gaves 110+ directly to PC through USB 3 adapter.