Many thanks for your patience. To answer your questions:
1. it would indeed appear that you cannot give notice to exit the agreement and will be expected to work until the end of its fixed term (if there is such a term). If there is no specified end date, they cannot realistically keep you employed indefinitely and in these circumstances you would be able to give ‘reasonable notice’ to end the agreement. What that is will depend on the circumstances, but it would usually be a month or more.
Even if you are at risk of breaching the contract, you cannot be stopped from leaving, it just means they can potentially pursue you for any losses incurred as a result. They cannot just penalise you though, they must be able to prove that losses have been incurred before they can go after you. Also there is no guarantee they will ever go to court over this and that is the only way they can force you to pay anything.
2. Yo8 can either take the risk I mentioned above or try to negotiate a mutually agreeable exit with the company. After all, if they know that you are not happy to stay, they may not want someone working for them who is not fully committed.
3. That is indeed possible, you are after all two businesses on equal footing and can negotiate the terms you want to be bound by. No one would have forced you to enter into this contract if you were not happy with the terms and as long as these terms were given to you in advance and you accepted the contract based on them, they can apply, even if they place the other side in a better position.
Does this answer your query?