Perhaps the best thing to do right now is to leave it all, stop thinking about it for the rest of the day. When I am faced with making this kind of decision with mine I find it stresses me out with the pros and cons of it all and trying to work out what to do for the best, but after a good rest often a solution will come. You say you're tired, and you obviously have a lot of things going on. You don't have to make any decisions right now

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It may help to write down a list of options with the pros and cons.
Scenario one:
Put them back together to see if they can work things out. Pro possibility of rekindled friendship. Cons Fighting and drawing blood. Thing to consider: If they are not drawing blood when together they may work things out. Pulling a scab off does not count as drawing blood, as this is not a deliberate act of hurting the other.
Scenario two:
The double-decker, one boar on each level. Pro - more space and room for enrichment, may stop chewing bars as more room may make them less depressed. Cons - cannot socialise and therefore may be depressed because of that. Note: Only experimentation can determine whether this is a good option for your pigs or not.
Scenario three:
Keep them as they are, remove the solid cover on the divider. Pro - more socialisation, may be enough to make them happy again. Con - bar chewing. Note: Bar chewing is unlikely to hurt the piggy, and the plastic coating coming off the bars is not likely to cause harm.
Scenario four:
Build the double decker, neuter them, get sows. Pro - socialised piggies with the potential to be very happy. Cons - money. More money spent on vets bills potentially, and money spent on neutering, plus you can't be sure they will get on with their sows until you neuter and put them together. It could end up worse in the end, or better. It's a big risk when money is tight and you cannot split the cages up any further, forcing you to rehome some of them if it all goes wrong.
Scenario four: Rehome both. Yeah, I know, it would be a massive heart-wrench to do so.
Scenario five: Rehome one and try the neutering and sow thing, but again you cannot know they will get on until they're together, unless you neuter and then go dating at a rescue. Again I know rehoming would be emotionally tough, I know when you take on an animal you have an unspoken promise to care for the animal for life, but things can and do change, and if you cannot come up with a solution where the pigs are happy it is something that may have to be considered. Try not to feel guilty if it happens, you didn't anticipate these issues!
If they are depressed something needs to change, and it may take some experimentation with set-ups to find a solution, but as I say, I'd best try to forget it for the rest of the day, as your subconscious will probably mull it over and you may find yourself pulled towards a particular solution or completely new solution when next you think about it

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