You are far better off with a combo modem,router this is much faster having a 3.1 modem vs the obsolete 3.0 ,it is much faster without question my speed doubled ,

and wifi signal Excellent , with coupon at Amazon under$250  could not be happier.

Motorola MG8702 | DOCSIS 3.1 Cable Modem + Wi-Fi Router (High Speed Combo) with Intelligent Power Boost | AC3200 Wi-Fi Speed | Approved for Comcast Xfinity, Cox, and Charter Spectrum

Audio streaming does not need much speed, a few hundred kilobits per second at most. The router can send tens or hundreds of megabits around the network. So you really need a lot of devices going at once before you have worries about an audio stream keeping up.

An old TP-Link Archer A8 serves my system just fine. Last I looked, under $100 in the U.S.

@yoramguy1 

All zeroes is because you're not executing the command as root. You need to log in as an Administrator first. Then at the terminal execute 'sudo su' and type in the password. Finally execute netstat. That should get you the actual stats.

No need to post any more data dumps - just look at the line for discarded for bad checksum ('netstat -s -p tcp | grep checksum') and check your Ethernet stats (netstat -i).

I’d try a Wi-Fi extender like the TP-Link AC2600 MU-MIMO and run an Ethernet cable into your streamer from the extender rather than using Wi-Fi and see if that works.  If that doesn’t work, get a better router and stop having to deal with this crap and still use the extender cause you’ll still be better off than Wi-Fi.  Either way, you’re better off. 

The biggest improvement you can make - once you get some router working - is the UpTone Audio EtherRegen switch.  It requires an ethernet cable connection to your router.  It will give you one "clean" port out to your streamer/player.  It gets rid of all the garbage generated in your router and its power supply.

If you got anything above entry level stuff, you'll hear the difference in soundstage and clarity.