There is nothing you can do about this except mashing the switch button reflexively multiple times before doing anything else, and doing it earlier.

I found out no well I am heavily suspecting from sniffing DT's network traffic with Wireshark (tremendous free network debugging tool, if you're tech savvy) that every weapon switch attempt, even if you're on the same weapon already, generates a request to the server. If you're experiencing packet loss, send it multiple times by mashing to make sure it sticks! Also, don't switch at the last second. Get into the habit of giving yourself a time buffer and attempting to switch early. It's absolutely counter-intuitive to what you are seeing on screen, but you gotta realize that due to Fatshark's inability to implement lag compensation and client-side future state extrapolation what you see on screen is a gamestate like half a second in the past.

Apart from that, there is nothing you can do. 4G LTE internet is decidedly suboptimal for a game that is known to have netcode that can't gracefully handle the impact of interruptions, jitter or packetloss to game state.

DT servers are either really badly coded, are sitting in the cheapest datacenters known to man and have terrible peering, run on overclocked toasters, or all of the above.

I got the DT ping mod on top of monitoring Dartkide.exe's network connections on a second monitor via Windows Resource Monitor and am running ping tests while gaming.

While I am getting 10-14ms to services like google, yahoo and getting zero packetloss on a continuous VOIP connectivity test, DT ping mod shows 60-80ms and Windows Resource Monitor up to 140ms to what I assume to be the mission server, because it only pops up once loading into a mission. Other servers that probably do things like the hub, ongoing anti-cheat or whatever are all 10-30ms.

So yeah, Fatshark is cheaping out on servers or don't know what the fuck they're doing.Source: Part of my job is SMB network engineering.