Slow write but normal read speeds on DS1821+

Forgive me in advance as I'm brand-spanking new at this and have little knowledge of networking. I just installed my Synology NAS and I'm experiencing consistently slow (7.7 MB/s) write, and normal (110 MB/s) read speeds. The same speeds occur when transferring a folder of many little files or one large file.

https://i.imgur.com/ox5LfuO.png

Some specifications: DS1821+ with 18TB WD Red Pro drives, Raid 10, MikroTik CRS305 switch (setting up for 10gbe in the future), cat6 cables coming out of the switch, using a Mac Studio. Internet is TELUS PureFibre internet (Canada) and a 30ft flat cat8 cable connects the modem to the switch.

I've looked through various threads and can't seem to find any posts with the same problem. Any help would be greatly appreciated. Thanks for your time!