You don't say whether you're single or not. I know my UC changes, depending on what my DH earns the previous month. I usually get nothing tbh. I got about 2 small payments last year.
The transitional protection reduces over time.
How it works
If your existing benefits are more than your Universal Credit entitlement, you'll receive a top up payment
The payment makes up the difference between your previous and new benefits
The payment is not time-limited, but it will decrease over time
If your circumstances change after you've made your claim, the payment may stop
£412 is a huge drop if you've been used to getting it regularly. I have no idea how they expect someone to manage that way. I suppose it's because it's calculated by a computer and not by humans.
Their maximum rent payment is far too low for the current rental market. How do they think people can pay their rent and everything else if they can't work, but are not given enough to live on?! That's what leads to benefit fraud IMO.
I would say that your rent should be paid before anything else. You don't want to rack up renters arrears and end up with no roof over your heads.
I know it sounds harsh (but I don't have any other answers and can only offer practical advice) but you're going to have to cut back even more.
Eg.
Stop smoking (if you do).
No alcohol.
No personal treats ie make-up, clothes, nice toiletries/skincare.
Meal plan.
No ready meals or frozen junk. Make all meals from scratch using a few cheap ingredients and cheap cuts of meat that you can slow cook and stretch to a few meals. Meat may seem expensive, but if you can make one joint last a few meals, it's often more economical in the long-run. It doesn't apply to all meats, such as beef. Pork shoulder is a good option as it's relatively cheap per lb, slow cooks well and goes a long way when shredded. Also very versatile.
Use bone-in chicken and not breast. Legs slow cook nicely and fall off the bone.
Oh, get a slow cooker! I got a huge refurbished Lakeland one on Ebay for £15 and use regularly.
Reduce fresh fruit (it's so expensive!).
Stock up on larger bags of rice and pasta. (In fact, anything that comes in larger packs is cheaper in the long-run than buying multiple small packs, ie loo roll)
Stock up on passata or tinned tomatoes.
Stock up on your fave herbs and spices. (Look at bags in world foods section of Asda, - about a £1 a bag and you get way more for your money than the jars).
No jarred or packet sauces (crap compared to homemade anyway!).
Buy big pots of yoghurt and not multi-packs.
Reduce portion size a bit if overeating (No shade here, I know I do!).
Use washing powder instead of tablets.
Buy cheap softener and add in a couple of drops of fragranced concentrated disinfectant (such as Zoflora. Plenty of cheaper versions/brands available now)
Dilute said concentrate with water in a spray bottle instead of buying kitchen sprays.
No chocolate, cakes, crisps or treats (Very depressing 😞)
No takeaways.
Heating on less.
Use less water (ie quick shower instead of bath).
Turn off lights in rooms you're not in.
Walk instead of driving.
Don't always assume the cheapest option is the best value.
I apologise if you're already doing these things and are still struggling. I know it's crap, but I don't know what else to suggest if you can't work.