I agree. Please don’t keep separating them repeatedly as it can just further destabilise a bond that sounds already a little tense. A temporary separation can be done once to determine whether they still want to be together. A reintroduction needs to be tried on neutral territory (not in the cage) and at that point a decision made on their future based on what occurs.
How long had they been together before you got them? When piggies move to a new environment then they go into a period of reestablishing their relationship, this will happen even in piggies who have always lived together. This is normal and to be expected but it should calm down If they want to be together.
The loud squeaking may be submission squeaking which is actually a good thing. He accepts his position as underpig and is telling Peewee so. Normally the dominant would then ease off once they have asserted themselves. If he isn’t then you may be in a situation where they may not be able to remain together because their relationship isn’t quite working. If their dominance is within normal levels then you need to leave them to get on with it and sort themselves out. If things go beyond normal dominance or one piggy (the underpiggy) isn’t happy but not as far as a full on fight, then that is when a one time temporary separation to determine the functionality of their bond can then be tried.
You separate them for a couple of days to calm down, but watch the underpig - so in your case Charlie’s - reaction. If he perks up when he is away from PeeWee then that is your answer that he most likely isn’t happy to live with Peewee anymore. It’s not Peewee’s reaction you use - the dominant will always be upset by a separation.
You can try a neutral territory reintroduction (if no full on fights have occurred) if you are unc
ear so they can make the decision for Themselves.
Your piggies are adults now so aren’t experiencing teenage hormones, but even adults get hormones spikes for a couple of days. One of my two boys becomes a nightmare for a few days in spring time but it settles within days (no separating required).
How is Charlie’s weight? It can be best to switch from the routine weekly weight checks and instead do daily weight checks where you have concerns. An unhappy/bullied piggy may be losing weight due to being unhappy and potentially not being allowed to eat as much as they need to.
How big is their cage? A boar pair need a minimum of 150x60cm but it’s recommended they have 180x60cm (there are commercial cages of this size, so a c&c is best as they can be made as big as necessary). Boars are more territorial and need a lot of space. Too small of a cage can be a problem when it comes to boars and escalate tensions.
They also need at least two of every item so they never have to share anything - multiple beds, hay piles, bottles Etc. It can also be best to not use bowls at all and instead simply scatter feed veg and pellets around the cage - this stops the dominant food hogging, but it also provides enrichment for them and encourages foraging.
However, even a large cage and multiple of every item will not fix a dysfunctional relationship so you do need to determine whether they still want to be together.
Bonds In Trouble
A Comprehensive Guide to Guinea Pig Boars
Bonding and Interaction: Illustrated social behaviours and bonding dynamics
Dominance Behaviours In Guinea Pigs