My advice: Try it and see if it works out.
Things to watch out for:
Reasons for switching projects.
What leads you to switch from one project to another?
Are you stuck?
If you are bored with your current story,
switching might help.
You might regain interest when you return to it later.
But it may also be a sign that your current story is boring.
Switching won't help that.
Better to throw out the boring stuff,
go back before the place where it started to get boring
and write something that's more interesting.
If you are stuck,
switching might help.
You might unstuck yourself while the story bubbles in the back of your mind as you write other things.
But it may be a sign that you're giving up too easily.
Or that you would benefit from applying a few creativity tricks.
The next time you get stuck,
try this seemingly stupid writer trick:
Just write the next sentence.
And the next.
Do that a bunch of times before you decide you're stuck.
Or try this:
If you've written yourself into a corner,
go back and change something earlier in the story
to give yourself a way out.
Or apply Wilhelm's Law.
Award-winning writer and editor Kate Wilhelm famously advised writers to "throw away your first three ideas."
Your first idea is probably obvious.
Most of your readers will have thought of it.
Many will have thought of your second idea.
Some will have thought of your third idea.
But your fourth idea,
that's probably fresh enough to seem original.
I've discovered an odd thing about Wilhelm's Law.
It's extraordinarily useful when I'm stuck
When I can't think of a single idea,
I apply Wilhelm's Law and think of four ideas.
For some reason,
it's easier to think of four ideas than to think of one.
Maybe it's because when I'm looking for one idea, I'm seeking perfection.
But if I look for four ideas, none of them has to be perfect.
This jiggles my stuck brain loose,
and then the ideas can come.
And of the four (or more),
at least one of them will be good enough to get me unstuck.
Most of the time.
Set aside vs. abandoned.
Notice whether you ever come back to the stories you set aside.
you don't really have multiple projects in progress.
(Hint: They're in progress only if they're progressing.)
In that case,
maybe starting multiple projects is a way to rationalize not finishing anything.
Many writers (and other people doing creative things)
have a fear of finishing.
Or, more likely, a fear of being judged.
You can absolutely avoid judgment by making sure you never finish anything.
But that ain't so satisfying.
What "in progress" means.
the distinction between set aside for a while and abandoned
is not obvious.
Note the last time you wrote new words on each project.
Count only new words as progress.
World building is not progress.
Research is not progress.
Outlining is not progress.
Only new words are progress.
At some point--three months? nine? a year? five years?--it will be harder to call it "in progress" if you haven't written new words.