Connecting Macbook Pro 13" (2017) to Dell P2418D

Hello. Got a compatibility issue. The Dell P2418D (a brand new 2K monitor) looks fuzzy when connected to my Macbook Pro 13" (2017, 2.3 GHz). It's connected through HDMI cable via an Apple USB-C multi adapter that has an HDMI port on it. The computer runs Intel Iris Plus Graphics 640 1536 MB

-I've tried changing resolution to something more suitable. No dice.

-Tried enabling HiDPI. Didn't work.

-Spoke to Dell support who told me Apple and Dell are basically frenemies.

The retailer suggested I switch out the HDMI cable to a direct DisplayPort-Thunderbolt (i.e. USB-C) cable. Does anyone know if that will actually make a difference?

(Note: I live in a country where (a) the cable costs $70 and (b) they don't really do returns on electronics.)