The main line drain is clogged or septic yank needs clean out.
The drain from the toilet to the main or the main itself is partially clogged or collapsed. There is probably enough room for the sink to drain but the washer puts out so much water all at once it can't get through and backs up into the tub and toilet.
People go in a tub then the tub empties it into the air.
Sounds like a venting problem. The washer is trying to push the water down the drain and the tub is an easier route. When it stops pumping, the washer drain become the vent and lets the air escape. You can try some drain cleaner in the tub and the washer drains. This may open it enough to help.
You have to use toilet more
You can run your discharge pipe from the washer into a laundry tub with the drain put in. After the wash cycle, the water will discharge from the washer into the laundry tub. Keep the water in there and replace the washer discharge pipe back into the usual drain. Let the washer run it's normal cycle. Take the clothes out and put them in the dryer or on the clothes line. The next step is the tricky part. You have to get a pump of some sort to put the discharged soapy water from the laundry tub back into the washer. This water will still be okay to wash the next set of clothes. I would wash the whites first, though. lol
It goes into the main sewer system. It will go through your sewer system and then out to the main sewer. That is if you live in town!
Connection of the washer drain hose to the tub drain is very important. This will help prevent leaks for example.
A clothes washer typically uses a water level sensor to determine the amount of water needed for a specific load size. This sensor can detect the water level in the tub and stop filling it once the desired level is reached. Some washers also have preset water level options based on the selected cycle.
There is the Haier HERHLP21E Portable Washer with Stainless Steel Tub.
it has a motor in the base and that connects to front and rear washer jets.
The Haier HLP21E Top Load Washer weighs 37 pounds.
You can effectively protect your tub from water damage by installing a tub water guard, which is a waterproof barrier that prevents water from leaking out of the tub and causing damage to the surrounding area.