The Wi-Fi the phones are using is coming from the Gateway and is a separate issue from the Wi-Fi the wireless TV Receivers would be using, which is provided by a WAP (Wireless Access Point).

There is an awful lot going on in your post and a lot of potential issues and thus potential solutions, and it is going to take a while to sort through all of them.

First question I want to make sure I understand...  You say you have "Ethernet" wired from the outside box to the Gateway and from the Gateway to the DVR and possibly some other receivers.  I want to know if you're sure the run from the outside box is Ethernet, meaning you have an externally mounted ONT for fiber or an 3812 iNID, or do you actually have twisted pair this is instead carrying VDSL2, not Ethernet.  Best way to check this is to probably do this (and it will address some other questions as well):

1. Go to http://192.168.1.254/ in a browser in your home
2. Click on the More Info button and see if the Uptime is shown.  Make a note or a screenshot of it.
3. Click on the Broadband Tab
4. Make a screenshot of all the information tables here: sync rates, attenuation, noise margin, error counts, byte counts, etc.  If you want, use a picture editor to hide your Public IP and MAC address(es).
5. Post the screenshot in a reply to this message so we can look at your information to try to guide you further.

JefferMc

The Ethernet cable to Gateway is outside from the twisted pair connection box for our home dial up phone. We have no fiber optic cable entering the property. The Ethernet was connected from this box by AT&T around 3 years ago. The original installation was regular TV cable.

OK? Thanks.

wasscal

Broadband Status

Broadband Connection Source	DSL
Broadband Connection	Up
Broadband IPv4 Address
Gateway IPv4 Address
MAC Address
Primary DNS
Secondary DNS
Primary DNS Name
Secondary DNS Name
MTU	1500
DSLAM Vendor ID	b5004244434db0cb

DSL Status

Line State	Up
Downstream Sync Rate (kbps)	32219
Upstream Sync Rate (kbps)	5046
Downstream Max Attainable Rate (kbps)	72732
Upstream Max Attainable Rate (kbps)	11106
Modulation	VDSL2
Data Path	Interleaved
	Downstream	Upstream
SN Margin (dB)	24.9	14.9
Line Attenuation (dB)	17.0	17.1
Output Power(dBm)	14.4	-12.2
Errored Seconds	0	2
Loss of Signal	0	0
Loss of Frame	0	0
FEC Errors	573	1217
CRC Errors	0	6

Timed Statistics

	15 Min	Cur Day	Showtime	Last Showtime	Total
Errored Seconds (ES)	0	0	0	0	0
Severely Errored Seconds (SESL)	0	0	0	0	0
Unavailable Seconds (UASL)	0	0	0	0	75
FEC Errors	0	16	573	573	573
CRC Errors	0	0	0	0	0
DSL Initialization Timeouts	0	0	0	0	0

IPv6

Status	Available
Service Type	native IPv6
Global Unicast IPv6 Address
Link Local Address
Default IPv6 Gateway Address
MTU	1500

IPv4 Statistics

Transmit Packets	2347219
Transmit Errors	0
Transmit Discards	0
Transmit Bytes	464023614
Receive Packets	46298631
Receive Errors	0
Receive Discards	0
Receive Bytes	2662943917
PTM Receive PDUs	46298631

IPv6 Statistics

Transmit Packets	66254
Transmit Errors	0
Transmit Discards	8227

You do not have Ethernet into your Gateway.  An "Ethernet cable" is really a misnomer.  You have a twisted pair cable that might could carry Ethernet, but it's not doing so; it's carrying VDSL2.  Your VDSL2 signal is strong, lots of excess capacity and a low error rate.  Which confirms that any issue you're having appears to be between your Gateway and the Receivers, inclusive.  This may also include cabling and wireless devices.  I wanted to cover that because if there's a problem there, we can waste a good bit of time on stuff trying to fix things that can't be fixed inside.  So thank you for that.

Now, let's explore exactly how you're wired inside the home:

1. The DVR is connected via Ethernet?  
2. Is this a single pre-manufactured cable or does it go through walls?
3. you have a wireless TV receiver about 30 feet from the Gateway; how far is the WAP from (a) the Gateway, and (b) the receiver?
4. Other than the Gateway and the WAP, do you have any other Wi-Fi Routers, Access Points or Extenders in use?
5. Have you tried unplugging the WAP for an hour or so and seeing how the DVR works while the WAP is turned off?