Truly frustrating situation

I’m currently based in Qatar and recently got selected for a job opportunity in Dubai. I passed all the interviews, and HR confirmed that I was selected.

About two weeks later, they sent me a Letter of Intent (LOI), which I signed and returned. Now it’s been another two weeks and I still haven’t received the official offer letter. I’ve followed up with HR, and they keep saying “expect it this week” but a week has already passed since that update.

For context, I hold an Indian passport, and during our last call they told me not to resign from my current job until they ask me to, because they need to wait for background clearance first.

How long does it usually take for a Dubai company to finalize the offer and visa process?

Is it normal for them to wait for visa clearance before issuing the offer letter?