The real question here is how much do you value your relationship with your family?
I think the family have already made this decision themselves. They're treating OP as a vehicle for making money (illegally by the sounds of it) and don't care for her as a person at all. Sadly, it doesn't sound like there is any relationship to speak of.
Sorry but you are to blame for agreeing to all of this. Your parents are only controlling because you allow it.
Sorry, but this is just nasty victim-blaming. It's the equivalent of saying that a wife who is a victim of DV is to blame for allowing her husband to beat her - "why does she allow him to do it?"
OP has been groomed this way from childhood, by the sounds of it - she is not at fault.
OP, the advice that PPs have given is good. Although your parents maybe don't realise/accept it, now you're wise to their devices, the power is actually all in your hands. They stand (and deserve) to lose a great deal (not that they haven't already taken so much from you) and gaslighting and creating FOG in your life is all that they have to rely on.
Every time your mother screams at you, know that this is her way of clinging on to the power she thinks she has - and she is probably scared, especially as you're obviously starting to ask questions and realise that things are not right. Effectively, she's acting like a toddler, who has no power of their own and only has screaming as a way to try to get what they want. The difference is that, unlike a toddler, she knows what she stands to lose.
Turn her screaming back on her. She sees it as a way to end the questions; I know it's not easy, but if you can treat it as her way of being unable/unwilling to discuss things, tell her you'll need to go over her head and contact the solicitor/bank/HMRC directly if she can't/won't help you. If you can summon up the strength to do that, I think you'll see her almost visibly deflate, as she realises the game is up, and she might respond with a last-ditch attempt at being all nicey-nicey with you, maybe asking why you would do 'that' to your 'loving' parents who've 'only ever tried to help you'. Too late: go over her head anyway. The fact is that, legally, you own the house, whatever your parents might try to do. Tell the official bodies all that you've told us and see where you can go from there.
Stop trying to please your parents or siblings, because they don't care about you one bit. Make the break from them and start putting yourself first. It won't be easy after the decades of abuse, but get all the help you need and break free.