A lot of things can cause "the mind to wander" and, frankly, I'm not a health professional but as a person who sometimes has trouble focusing I somewhat sympathize. There are times when I simply can't sit down and enjoy myself, and there's nothing that can be done about that. Usually times of high stress and anxiety.
But outside of those extreme cases, there's generally a few things here and there that can help alleviate. The first, and maybe almost stupidly obvious one, is to do some of those tasks beforehand. I don't have to stress about doing the dishes or paying the bills or returning a call if I just do it beforehand. Logging into the bank app is just 5 minutes, why worry about it otherwise.
Another is to get comfortable and shut yourself off. Leave your phone in a place you can't reach from wherever you're gaming (or watching a movie, or reading or studying. Your phone should actually be in a different room every time you don't immediately need it) as well as any other electronic devices. Close the windows and doors, turn off your PC. Make it a bother to stop enjoying yourself.
Take a bathroom break (or if its in the evening, a shower+grooming) and maybe have a snack or a full meal. Have a bottle of water nearby. That crosses out basic biologic annoyances (until you need a pee break but that's at least a healthy obstacle).
Exercise a bit. Sounds out there, but exhausting yourself physically isn't only healthy, it also takes your mind off a lot of things. Since that's a relatively boring activity that can also have your mind wander, have some podcasts handy, but something light and preferably with 2+ hosts so you can have several voices in your head that aren't yours but also don't need to follow a story or anything heavy. Going on a walk while listening to a 1 hour episode should be good enough (and something we all should do regardless of attention issues)
On the subject of podcasts, I've found that some games aren't gripping enough to draw my attention or are repetitive enough that I don't need to dedicate all of my attention to them, so I've dubbed them Podcast Games and do both at the same time. Roguelikes do very well in this regard, as well as management games, or anything that isn't story heavy (or if the story blows) and where the sound isn't exactly necessary.
And sometimes, ultimately, maybe you just aren't really in the mood for a game. There are hobbies of mine that I enjoy, but don't do much because I'm not "in the zone" as often, like reading or watching a TV series. So if gaming is like that for you, swap around and enjoy yourself, time spent doing something you like isn't time wasted.
Optional: I've found that I'm much better at sitting down and watching a movie or a show when I have someone alongside me to chat up. Maybe having someone along to play/watch together, or simply streaming through Discord for a friend might be a solution. You'd be surprised at how many other people are also bored and would accept an invite to watch you play while chatting about their day.