They are frequently targeted because they offer enterprise grade configurations at consumer prices.
Which means, there's a lot that can be misconfigured, and a lot of short staffed and under budgeted IT departments that deploy them, which means they are a good payoff when exploited.
That's the bad part, and the good part.
You really cannot beat their price point to value for professional grade networking equipment. Just take the time to understand what you're doing when doing your configurations, and keep them updated.
Did you mean to send that reply to me?
I ask because I'm not quite sure what specific suggestions you're looking for.
But in general, I would suggest not exposing port forwarding.
What services are running behind NGINX? What router/firewall are you using?