OP, I feel for you.
A family is like any management structure.
The tone is set from the top.
If management is poor it filters down.
You have done step one. Removal of all electronic stimulation. Do NOT relent on this point. Your children need a total detox.
Give them a bag exact to go from room to room tidying up.
Get the children to tidy every room with toys.
Get the children to tidy their rooms.
New house rules.
No food beyond the table. Stick to this.
Your husband sounds lazy. He is not a great example to the children.
Children respond to a tidy home.
If they see your husband doesn't give a damn, that the place is a mess, they lean into it.
Keeping them completely away from electronics will tell them you mean business.
Tell them clearly you are no longer putting up with their attitude. And mean it.
I remember years ago a couple of my children were being very bratty and fighting with each other and I had had enough. I told them to get their hats and coats on and get out to the garden to play and work off some steam....they got bored after a while and I told them to kick a ball to keep warm, but they were not coming back in until they improved their behaviour.....they were much better when they came back in and just the threat of an extended playtime in the cold weather was enough to put manners on them.
Children will walk all over you if you give them the chance.
They HAVE to respect you.
They HAVE to believe you will follow through.
Your two need their cough softened big time if they are laughing at you.
Believe me you do not want to be dealing with them as teenagers if they are laughing at you at 7-8.
You can turn this around.
You would not believe what can be achieved by turning off all electronics and telling all of them, including your husband that you have had enough.
You have a lot going on. Make Christmas as simple as possible. Cut out anything except the basics.
Your family need you well.
Take care of yourself and tell your husband he needs to step up as you have had enough.
Wishing you strength 💐