Is there a container, similar to the Diaper Genie, but for adult diapers? Need it to twist airtight, to help with the terrible odor in the bathroom.

We just put the depends in an old shopping bags, tied up and put them outside after every change.

My mom wore the S/M size and I could fit those inside one of those doggie poo bags and tie them up, the bags sold for those small kitchen trash cans are a little bigger. I then dropped that into a small lined trash can with a tight fitting lid which I emptied often.
I tried lots of products inside the can itself to mask odours but in my experience they just added something pleasant over something bad (I can remember joking with people on the forum about the wonderful new scent of sh!trus🤣).

@babsjvd

I often lined client commode with a plastic liner bag with kitty litter and baking soda in it.
It works wonders for smells.

What I always did with the adult diapers is tie them up in a small plastic bag and then to the outside garbage can immediately.
I had a few care clients who stored their outside garbage cans in the garage and I worked the night shift alone and wasn't willing to trek across the dark yard into the garage. So we kept a small, covered garbage can lined with a bag on the porch outside. It got emptied and we changed the bag once a day. If you tie the diapers up in a small plastic bags and put them in a garbage can lined with a bag that has a cover, you won't smell anything. Keep the can outside on a porch if possible.
If that's not possible, sprinkle a little Arm & Hammer brand cat litter deodorizer in the bag before the soiled diaper gets put in.
Tie it up and you won't smell anything.
We used to put a little of the deodorizer in the bottom of the trash can and in the liner bag. It really works.

I use the Akord Slim Incontinence Disposal System with Odor Lock,
You can look it up on amazon.

I know it might be an additional waste but I actually wrap EACH nappy in a separate small plastic bag (tie it closed) before disposing it in the bin. The bin is then lined with a scented liner. I try use biodegradable bags,.. not that it makes a huge difference when the nappy itself is not very environmentally friendly. However sometimes Mum will place diaper direct in the big bin and I can instantly tell.

O yes, like Clairsmum says. You roll the diaper up. I even tried to get as much of #2 off I could. Just looked up "baby diaper liners". These are used basically for cloth diapers. You put them inside the Depends and they can be flushed. So most of the "mess" goes on them. And they are flushable.

You might also try a spray bottle with pinesoil or vinegar and water mix. A few sprays into the can and room can mask odors. Vinegar masks urine well and pinesoil for cans with #2 until it can be emptied.

Small plastic trash bag to wrap each one separate is simplest method. You can tie them shut with or without wire ties. The wire ties will do best because you completely seal it. Tying the bag will still allow some odor out.

Then to keep smell out of your outdoor can - dump all your tied up bags into one large trash bag and place in the can your trash company picks up. And don't leave outdoor can sitting in hot sun between pick ups!

Ideally, if you had a small chest type freezer that could be used only for these items (and for scrap food items) you could eliminate all the household odor. Keep a large trash bag inside, dump daily waste and haul it all out night before city trash is picked up. Prevents smell AND keeps dogs/varmits out of the trash. I've been doing food scraps like that for years.

I just take them to the garbage can out side. It has a lid to reduce odor.