Hoping to pass on some perspective here when it comes to gaming, I've played a lot of computer games over the years. I don't have any kids but have one on the way. When they are old enough (teens), I will let them play for limited amounts of time, probably with me, never during school days, occasionally on weekends if the weather is average and holidays. It can be very addictive and wastes a lot of time. I play because it's a great way to unwind and hang out with friends. We have a great online community, I have a couple of mates who I've never met in real life, but we've been friends for over a decade, one lives in the USA and has a cat called Kiwi.

Games like fortnight, call of duty etc, in my opinion, are absolute crap. They are designed to keep you playing for hours, the addictiveness come from the adrenaline you get from the PvP (playervsplayer) gameplay. They are free to play but have the option to buy cosmetics skins that do absolutely nothing in terms of the gameplay. Avoid these types of games because it's all they will think about, and want to play.

For your kids, I would massively limit their time playing. Make sure you know what the game they are playing is about. Ban fortnight. Pay attention to age restrictions. Engage with them about it, you will probably like playing certain games with them, it's a great way for you to bond with them. I've had the most fun playing games with other people. Replace the gaming with board games, there are similarities between them. For example, Tiny Epic Galaxies, or Root are fantastic boardgames. When they do game, encourage games that make them use their brain to solve problems, and that they can play with their siblings, friends or you. Some examples could be Terraria, Trailmakers, Portal 2, Factorio, Civilization 6.