I've done lots of moves (7) over the years as a result of buying houses to do up and sell.
When it was just me and DH (and smaller properties) we "moved" ourselves.
This meant in the two weeks leading up to the move we ordered loads of boxes, packing tape, bubble wrap (you WILL need far more than you think - double you're estimate) and started packing up each room ready to go (starting with the least used).
By the night before we would have the bare minimum left (think kettle a couple of mugs, our bed and clothes for the moving day) and everything else was packed up in a single room nearest the door for access.
We'd hire a large van and that would arrive the night before.
Once we had the keys we'd start transferring boxes/furniture. It took pretty much all day and was exhausting.
The last 2 moves with children we've admitted defeat. We're in much bigger houses now with vastly more furniture and all the kids things.
Tbh I wish I'd given in sooner....
Professional movers are a godsend. They came in like a pack of locusts with all the right packing equipment (including specialist items like clothes rails and sofa covers that were like large Jiffy bags, similar for mirrors and paintings etc) and had us all packed within 5 hours.
On the other side we had to do the "unpacking" though they put the furniture in the right rooms (we could have paid for them to do this but actually wanted to unpack ourselves) and a week later they collected all their packing equipment.
If you're a family of 7 I'd say it's a no brainier to use a packing company.
There's no way (without an army of family and friends plus paying for vans, packaging) you're going to be able to do this in the time you'll have.
It's not cheap but it's far less stressful.
All I had to do was waft around "looking" busy until they cleared a room and then I cleaned it ready for the new buyers.
Honestly - book movers....