I've seen lighting do VERY strange things: take out 1 LAN port; take out the DSL modem's incoming phone line port; go from DSL phone line, through the modem (blowing it up) and take out PC's Ethernet port (most common here) and the grand prize winner of strange: come in through phone line, get the DSL modem and the fax machine and it's DSL filter where plugged into the phone line then kill the onboard video of a circa 2004 Dell Dimension 2400. I had to install a video card but get this...it didn't even bother the Ethernet port on the PC that was plugged into the DSL modem that got blown up. Go figure! Like I said, lightning does pretty much what it wants to, at least in NW Alabama. We get it so bad that the thunder knocks pictures off the wall and sets off car and house alarms from the sonic percussion.
I agree with
@tangent and others here, turn off the DSL modem/wireless router's Wi-Fi and install a BETTER wireless router on a LAN port of your DSL modem/wireless router. However, before plugging it in the routing function of your chosen wireless router should be disabled, turning it into an access point only. You do that by turning off DHCP and giving it a static IP, subnet mask, gateway and preferred DNS. I have a Ubiquiti NSM2 as my AP but my ZyXEL DSL modem/wireless router performs DHCP and its wireless is off.
And lastly, I can relate to
@Stanley71 's dilemma of being out in the country, I'm so far out my DSL REALLY SUX: I have CenturyUNlink of 1.5meg DOWN and 512K UP. Yes, that's not a misprint. It's akin to 2 Dixie cups and some string (or wire, I guess). We cannot even stream Netflix of Amazon Prime video.
@Camit , personally I'd be VERY happy with 7 Meg down. Ya'll need to rejoice with your 4, 8, 20 and 60 megs comin' down the wire!!