Minecraft allocate more memory Launcher 2.53?

I own the Launcher 2.53

when I use the JVM arguments, e.g. Xmx = 4G (I have 16GB), then Minecraft crashes.

For the JVM arguments, for example: -XX: MaxPermSize = 256M

If I go there for example 512M, 1024M… Then the game crashes too.

What is the right solution? I would like to play Minecraft with mods.

The "=" has lost nothing there.

The value is set directly behind the text.

The = is specified in the example given by Minecraft. Without = did not change the problem.

Does it look like in the video? Java currently?

The video is from 2017. The launcher looks completely different today. Java was completely freshly installed.

How does he look like you? That's what it looks like today

Do you have 64bit Java or only 32bit?

64bit

This is not the official launcher but the T Launcher.

For one, you do not need the arguments, because there's the scroller under it. On the other hand, Java only has 1.5GB of RAM on your PC. Control Panel → Java → Java → View → Under Arguments "-Xms8GB" then you should be able to assign more.
Or:

Many thanks for the help