I bought this router few days ago, previously I had Archer C7 v4 which has only USB 2.0. I bought Archer C3150 V2 because it had USB 3.0, USB 2.0 port, Beamforming, MU-MIMO and other cool feature. I...

But prefer the higher versions, in your case V2 because Tp-link completely forgets older versions and don't provide any firmware for them.

These versions represents minor hardware revisions, usually regarding RAM and flash storage capacity.

I had a Archer C7 v4 in the past and couple of 841n routers with dd-wrt. They work fine, dd-wrt for v5 is avaliabe at,...

I agree. But they should at least release a new firmware with scheduled reboot and offline downloading. The router has a USB 3.0 if it had the offline downloading feature, it would be the best device...

Telnet is locked down by TP-Link, try using dd-wrt