R6300v2 Disconnecting Internet Exactly Every 30 Minutes

> [...] every 30 minutes on the dot [...]

   I know nothing, but I wouldn't expect anything in the router to
operate at that interval.  However, ...

> [...] I am using their Netgear R6300v2 router [...]

> [...] My router admin shows firmware version V1.0.3.22_10.1.13SW [...]

   The key there is "their".  Apparently, you have a router with
ISP-specific firmware.  Another example:

      https://community.netgear.com/t5/x/x/m-p/1783442

   I can imagine that there's some oddity in that "SW" firmware which
might cause (periodic) trouble.  (But what do I know?)

   Knowing what I do, I'd see if I could get my hands on a different
router, swap it in, and see if the problem persists.

   Does complaining to the ISP help?