COM4 should be ok. Not tried a Chinesium USB Serial for many years, as I now use an FTDI adapter on both my Macbook & windows for various serial stuff.
The error you got looks like a windows driver issue.
I have this information but what one is the one to search for the driver as I used the top one and it's sending me into ateas I'm not comfortable with.
Before you install it, you need to delete any Microsoft driver first. See post #31 in this thread. (I suspect the "wch.cn" is from Microsoft, hence your issues.)