Since ~3 days I've been suffering disconnects in every game I play, like every 2 minutes. I don't dare play ranked games because of this, and the game is quickly losing its fun. Tried everything but a reset to default on my router, but it seems to work just fine, no ping losses from what I can tell. Re-installed the game, checked the cables and so on.

No I don't have Killer Network Manager installed.

From what I can tell it's only Magic Arena that don't work like it should. It has run smoothly on my same rig since I joined back in the summer, only new thing is my router but I've played Arena since christmas eve through it, with no problems.

Anyone else with the same problem?

I had a similar 2-3 day span around Christmas. I dunno what that was, but it passed. Hopefully yours does, too.

I haven't had any issues. Might be a router issue on your end. Might be a good idea to power cycle it. We run all devices wireless in our house and i need to do that once in a while to reset half-open connections

What is "power cycle" it?

Unplug the router for 20 seconds, plug it back in and then wait for it to come back online. It will refresh the connection ram in the router. I use torrents quite a bit and they are notorious for leaving half open connections. It's like how your system runs after cleaning the registry. Before that the registry is looking for all these paths that no longer exist and wasting resources. Same concept with the router. It is still looking for those connections it has half open.
It's the simplest fix most of the time. Also, if you are like me and have a separate gateway (the router/modem your isp has you hooked to before your router) you would want to unplug both, plug the gateway back in after 20 seconds and wait for it to cycle back to being totally active and online and then plug your router back in.
I hope it helps. I see a marked improvement in our connections and speed after I do that to our equipment.

I've unplugged my router, was among the first things I did. Not sure I had it off for 20 secs tho, will try it again. Nevertheless, thank you!

Found the problem! A cable was apparently internally damaged, I switched it out.

Reminds of my CISCO class, where the first rule of computer repair - 90% of the time, it's the cables.

Yeah. Kind of strange though, only Arena gave me trouble, it must be a really sensitive program.

That was my next call. You are right. It's either cables or a good reboot most of the time.