Hi, vencakratky,
first, if you have your TV on already adding on command does not bring you a visible feedback if it really works. Try standby or pow (also described in the link). Secondly have you ever tried to connect all your devices (HDMI port # i think does not matter, but who knows nowadays ) and scan them? if they are visible try on and standby and pow or any other visible feedback commands volup and see if they respond. Do not forget maybe you need to add the device # as stated in some examples. If you go one page before, there is a snapshot of my other setup, I have an older samsung tv, connected thru a Receiver and then RPi 2. the Pi sees all 3 devices. So if your Amiko is CEC compatible and the HDMI cable is good, Pi4 should see and control as well.
Also there are options (i am not sure if you touched that before) inside Kodi when you go Settings/System/Input/Peripherals there you can edit your libCEC which can also affect your setup (+ you have the samsung tv, but honestly i do not see much of an "edit" in TizenOS there)
I believe CEC is not so straightforward as sometimes it is described, i needed to 4 times install from NOOBs when I was finally found the almost right solution (since my remote is not 100% perfect ) and I am still waiting for my new cable from Amazon...