L1 to H1B transfer, not joining who sponsored H1 but joining X company

I came to US on L1 visa. Got my H1B visa from X company but now i wanna join Y company. Now company Y is ready to transfer my visa, if they initiate the transfer process by any chance, company X will create any issue.
Visa sponsored by X company but can i join Y company?

Note: my payroll is not started yet with X company.

Employer X will not know about the H1B transfer to employer Y unless you tell them. So technically they can’t create any issue. Once the transfer is approved (it will actually be a new cap-exempt H1B petition by employer Y) you can resign with current employer and start working with new employer once your assignment with current employer ends.