Is the payment plan overall okay?

Is there even the possibility of negotiating the contract and the payment schedule? Overall, I would rather try to focus on clauses like "assignment of the loan disbursement," "assignment of the order of disbursement," "assignment" of the right to the house," etc. The payment schedule is a topic unto itself, since even the completion of a trade is never clear-cut. Is the window installation only completed with the final adjustment of the opening mechanism before handover? Not to mention the "start." The best payment schedule is useless if the construction company can request money from your loan at the bank at will and it then flows directly into their account.