Hey blazejp0 --

It sounds like this is going to come down to speed. Once you are able to quickly form chord shapes and almost simultaneously strum the next chord, this open-string ringing will become less of a problem. I suspect that's going to be the answer for you.

Eventually, there's extra muting you can do as time goes on. If you are not doing this already, you will learn to lightly touch adjacent strings with your left hand fingers (the ones you aren't fretting) so they won't ring. For example, if I am playing a basic three-finger C chord, I lightly touch the low E string with the extra flesh of my ring finger, so I can strum straight through all the strings and that low E won't ring out. (E is part of a C chord but it sounds clunky if it's the lowest note in the wrong context, and for most basic chord strumming).

I tend to do the same thing when I strum a D major chord. I automatically wrap my thumb around the neck a bit to mute that low E string. This is almost an advanced thing you naturally start to do to avoid extra strings ringing out. It's a way to be able to strum more freely.

Especially if you play with a lot of distortion, you find a lot of ways to keep strings from ringing. (Although I see you are on acoustic.)

But that type of muting is probably for later. It sounds like getting those fingers into the next chord and quickly strumming it will solve your problem. That speed increase will just come from practice.

It's good you are aware of these string ringing issues, because it means you've got a good ear for this and will eventually solve the problem!

-Carl.