Of course, the employers may fear to loose their power. But thinking more about the Basic Income could change their mind as they find out that the Basic Income actually gives flexibility to the work relationships.

How could this be possible?

Let's start from assuming that the Basic Income is for all. So most of several different social benefits and related regulations (included restrictions) will make no sense.

When one has a Basic Income then he/she probably could rather agree with partial time / small works. Today, if you earn even some dozens of euros, if often replaces even bigger benefits. With an Unconditional Basic Income - when you are working your income is always bigger than without work.

UBI could probably make easier for employers to cancel the work relationship with a worker. Assuming that the workers "get stronger" it would be fair.

No (unnecessary) jobs would be created just for creating jobs. But the people who remain without job just will not be poor. They could, after all, to show the door to anyone who offer "jobs" that seem to be rather illegal. In the best case they are encouraged to test their ability as enterpreneurs.

The basic income is not a fish but a fishook for all. With the feed... and lot of canned sprats to stay alive when fishing the fat and fresh trout.