Multiple job offers in Singapore

You can only have ONE ongoing EP application at any one time.
That means you'd have to cancel the first EP (by terminating your employment contract with company 1) BEFORE the company 2 can apply for one.
The new application is then assessed on its own merit - and there is no guarantee it will be successful.

The only lower risk alternative, if timelines permit, is to get EP 1 issued (by coming to Singapore and starting work at company 1) and THEN let company 2 apply.
You then still have no guarantee that EP 2 will be issued, but in that case still have your job at company 1. This, if successful, it means a 3 - 5 months later starting date at company 2. Are they willing to wait?

I am already working in Singapore as a software engineer on an EP from 10 months

Our company might close soon due to covid and I was trying to switch company  and applied at company1. Does canceling application1 reduce the chances of application2

Yes, it will have a negative impact, because MoM does not like job-hoppers.
But with a good explanation (i.e. company will close due to economic situation) this would be minimized.