I've read every post on here and feel well qualified to comment.
Firstly - think about yourself and what you need. My useless Ex basically wandered into debt and was pretty passive about it. He was a low earner and although a sweet guy was honestly just useless when things got tough.
Don't get chickens. They are animals that require an outlay and attention. Feed costs money and if you get rodents/red mite it's a right pita that you do not need. Nobody needs that many eggs. Yes I had them and they were gorgeous but not going to save us much money.
We have solar panels. Don't bother. Pigeons bloody nest on them and they are a fucking pain. Ours came with the house and yes they save on bills but like other people have said it takes years to recoup the cost and see a saving.
Yes to heated airer and dehumidifier. Personally I'd alternate cloth nappies and disposable to make it more manageable.
Air fryers and slow cookers are good, but again they don't make a significant change unless you were previously shopping at Harrods and cooking each chicken breast individually.
Freezers are good but stuff gets lost and forgotten. There is a mental load here around shopping, batch cooking and then defrosting. I wouldn't have another chest freezer but I would get one with drawers.
Finally decreasing outgoings only does so much. Increasing income will be the key here.
Also - the way your DH seems to be so passive and useless will really get to you.
I remember selling a load of clothes on EBay and my ex came home with an Adele CD he'd bought at a service station. It just highlighted how we were not on the same page about budgeting and spending.
Oh and yes we had YNAB but I just do a spreadsheet now so no cost there.
Good luck.