I have two DC, 7 and 3. The youngest doesn't sit and watch TV for long so isn't a problem.
My eldest, lately, seems to be developing an addiction to TV. He doesn't have it in the morning before school, and our mornings are definitely easier as a result. After school he is allowed to watch it to unwind, especially as I WFH so if I collect him, I am then working for an hour or so (younger DC is in nursery). He does after school activities on two weekdays so it's limited to about 45 minutes maximum on those days but on the other days he can have up to 1.5 hours, maybe even 2 at a push.
His listening has gone really downhill recently so I've implemented a TV reward chart, a basic amount of 30 minutes TV a day, and the opportunity to win or lose some depending on listening. Yesterday he had won extra so had 50 minutes, but on Monday he'd lost it all so had none.
On Monday he whined and whined without it but after a while went off to play happily with his sibling. He managed to win 10 minutes which he watched before bed.
Yesterday after the 50 minutes, he turns it off with little fuss, but then asks to watch more and more later: "just a little bit pleeeeeeasseee". It's like an addiction at the moment in a way it didn't used to be!
I think it might be the stuff he watches (strictly no Youtube but has free reign of Kids' Netflix/Prime etc so watches rubbish cartoons a lot) so I'm torn whether to try an all out ban, or maybe limit to less trashy stuff eg CBBC.
In reality how much do your kids have? And does it impact behaviour? The only other screen my DS has is a Kindle Fire tablet which he's allowed to play on the weekends, it's only ever about 30-40 minutes a day though. He mostly plays Sonic on that.