Any cell routers with external antennas?

I too have the Arcadyan KVD21 5G gateway and I'm surprised that they didn't include a port for an external antenna. You might want to check out Nater Tater on YouTube who has tutorials on how to crack open the KVD21 and attach an external antenna. It's definitely not for the faint-of-heart, but for how, it's the only hack I know of for this device.

While I don't live in a pine forest, I live in a heavily treed community where the trees form a tunnel over the entire roadway. It adds to the challenge of getting a good signal from T-Mobile for my home Internet. I've only had the gateway for two months, and I'm satisfied with the bandwidth I'm getting, somewhere between 35-70 Mbps, and only on 4G LTE. Nonetheless, it's more reliable than Xfinity and definitely less expensive.

One last thought: I have read a lot of threads on this forum of people who started out great with T-Mobile for a year or so, only to watch their service go downhill from there. I'm not sure what happens, but it appears it's not uncommon to go from great service down to unacceptable.