Adguard / DHCP / add Block MAC address

[Stanojoski]

It is my first time to open discussion in here, I didn't know where to address my problem, i added on home assistant forum, but without success.
So my idea is to put some MAC block list to the DHCP server, because this is happening at my home:

I use heavily DHCP server from Adguard, I know it is not its primary function, but it works very well, but..
My TV box keeps getting an IP from my AdGuard DHCP server. It should get it from the ISP.
I guess that would be 10 minutes for someone more experienced. @frenck probably 2 minutes :)

Thank you.
Sorry if i am not writing at the right place.