How to pass all keybindings to child window in `i3` WM?

Question

Is there any way I can tell i3 to pass all system keys to window I am focused on? I don't mind if I can't switch off of that window - assume that it can be closed from inside.

For example, I can run sway from i3 and I want to pass keybindings here, if I am focused on it - for example, mod + 2 - to change workspace tab to second.

What I tried:

• At first I thought, that if the window in i3 is in full-screen, the keybindings will be catched, but no.

• Then, I was trying to use something with for_window [...] focus, but wasn't able to get any results.

• Then I was trying to make something with bindsym and xdotool (found some question about firefox here). For example, I achieved changing sending keys from CTRL + SHIFT + C to CTRL + C but not passing them throw - it causes infinite loop.

Am I missing something obvious? I am quite new to i3.