Your question has only one answer: 无 (in the Chan/Zen formulation of 'unasking' a badly-formulated question).

At least for me, finding work is hard and knowing i could be easily fired for the first 6 months is stressful.

This is irrelevant in a properly socialist world. In a properly socialist world your basic needs would be met so losing your job isn't the source of stress that it is in a capitalist world where your basic needs are a negotiation strategy.

ANY job, even working in whatever passes for a McDonald's in such a society, has skills and abilities you must have to perform it. Not all people can do every job. This is most obvious in heavily technical fields, obviously (like, say, medicine or technology), but even working as a janitor has things you need to do which you may be socially, physically, or psychologically incapable of doing. And the only way to find out if you can do them is to try it out.

But…

With your basic needs met, if you try out and fail you're not risking your health and very life. The desperation isn't there. So I'd say yes, obviously, there would still be a period of evaluation for fit and ability in jobs in a socialist world. It's just that failing at it wouldn't be the devastating experience being fired in a capitalist world bears.