Remap Logitech T400 middle click

I have a Logitech T400. This mouse has two "middle click buttons":

Button A is mapped to the regular middle click, which is what I want. But button B is mapped to Super L which is useless, I want to map it also to the regular middle click too. I am using Ubuntu 20.04.

I looked into this question of someone asking the same. None of the answers worked for me. I also tried

xmodmap -e "keycode 133 = Pointer_Button2"

as suggested here which also did not worked and I lost the real Super L button in the keyboard which I would like to conserve.

I have tried with the application Input Remapper with this configuration:and it works as I want, but it breaks the soft scroll of the mouse so it is not a solution to me.

If I run xev then one click and release of button A produces this:

ButtonPress event, serial 37, synthetic NO, window 0x5e00001, root 0x7b2, subw 0x0, time 886786, (68,93), root:(939,1634), state 0x0, button 2, same_screen YES
ButtonRelease event, serial 37, synthetic NO, window 0x5e00001, root 0x7b2, subw 0x0, time 887362, (68,93), root:(939,1634), state 0x200, button 2, same_screen YES

and one click and release of button B produces this:

MappingNotify event, serial 37, synthetic NO, window 0x0, request MappingKeyboard, first_keycode 8, count 248
KeyPress event, serial 37, synthetic NO, window 0x5e00001, root 0x7b2, subw 0x0, time 893980, (68,93), root:(939,1634), state 0x0, keycode 133 (keysym 0xffeb, Super_L), same_screen YES, XLookupString gives 0 bytes: XmbLookupString gives 0 bytes: XFilterEvent returns: False
KeyRelease event, serial 38, synthetic NO, window 0x5e00001, root 0x7b2, subw 0x0, time 894604, (68,93), root:(939,1634), state 0x40, keycode 133 (keysym 0xffeb, Super_L), same_screen YES, XLookupString gives 0 bytes: XFilterEvent returns: False

How can I remap button B to "regular middle click" and (if possible) keep Super L working in my keyboard? If no extra apps/programs have to be installed for such simple task, better.

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