Highrez

To put it as simple as possible; I need that, when two mouse buttons are pressed simultaneously, it will trigger a keyboard command instead.

More specific: if right mouse button is clicked, and then also Mouse button 4 (as chord), that should trigger "R" on the keyboard, instead of keep firing the mouse buttons.

I'm sure that should be possible but I tried several ways and nothing worked so far.

I appreciate any help!

Setup Button Chording on the right button and then in the chord setup, set button 4 to Sim Keys and enter 'R' in the input
Does that work?

Dear Phil,

thanks for the answer. I tried your suggestion during the weekend.
You guided me in the right direction - thanks!
It worked most of the time. I use the chord for reloading in a game, and for some reason there were issues with consistency - in about 7/10 times it worked, the other times it didn't activate. Also, the button pressed secondly (Mouse 4, which is crouching in the game) still activated which was not wanted ("block original mouse button" was checked - that should be the setting, i guess). So, most of the times the character would reload, but then always duck down at the same time.
I wildly, and blindly, tried all checkboxes in the settings.

Now, l I found the settings (also changed mouse button from 4 to 5) for a 10/10, success rate!

I wanted to attach a screenshot of the relevant settings, if you're interested maybe you could spot what setting has made the difference.
I'm not sure if the action on the second button is still activated, but since I changed the buttons it is not noticeable anymore, like it was with the crouching.
Either way, it really is a huge joy to use now, and I'm impressed that you've answered personally so quickly - thank you again.

I'm glad you have a solution....

Ive updated your user level so you can now post screenshots, links etc. (NOTE: Thisis usually automatic after 4 or 5 posts).
It would be good for others who are looking for similar solutions.