I submitted several resumes. Once you sign a contract with one company, you can't go to other companies.

I think so, too. It will cost a lot of money if you break the contract after signing three parties. Now most companies are competing for talents. After signing, I will take office in June and July next year. If you are afraid of meeting a better company, don't sign it first (of course, if people are interested in signing a tripartite contract with you), but the general company will give you 1 month or so to think about it (at least I met it). When it's due, people will take it as your initiative to give up.