The lure of executing multiple ideas at the same time? Is it good, bad, or dangerous for all of the startups?

Simple answer. Yes. Do less. Kick ass at the things you do.

I too was very much a doer of everything when I started out, and learned the painful way that one of the most successful traits I see across the successful entrepreneurs I meet daily is FOCUS.

Try to start with the big questions. What problem are you solving, for who? What are your own personal goals (do you want to sell the company? reach a certain revenue level? etc) Then work backwards and work out the minimum things you need to do to achieve that. Then say a firm no to everything that comes your way. Its hard, a lot harder than saying yes but saying no is a highly underrated strategy that is well worth investing in.

Cut out all pointless calls. Cut out all pointless meetings. Free up your calendar so you have time to breathe and think, and to focus on the (real) priorities.

Don't fool yourself into being busy. Working hard doesn't actually achieve success despite what media mumbo jumbo will try to tell you. Working smart does.

Happy to share more in a call including some practical tips and tricks I've learned along the way from a fairly unfocused entrepreneurs to a much more more focused one.

Short answer: lean methodology. If done correctly, you can do a market validation test/MVP in a matter of days/weeks for each of the 3 ideas and at a minimal cost. Based on the results, you should decide which idea to invest all of your time on.
Here's a link to a past answer I gave explaining how to do market validation: https://clarity.fm/questions/6423/how-do-you-do-market-research

If it's too hard for you to let go of the other two ideas, and can't delay them, recruit a founder who will be the CEO (not easy relinquishing control, but better to have a part of something than a part of nothing). But only bring in another founder if you're the type of person who can 'let go' - if not, you're just going to be sucked in and eventually find yourself working on all 3 ideas.
[I'm curious to hear what the ideas are. ]
I've successfully helped over 300 entrepreneurs and would be happy to help you. After scheduling a call, please send me some background information so that I can prepare in advance - thus giving you maximum value for your money. Take a look at the great reviews I’ve received: https://clarity.fm/assafben-david

Indeed a very good question, I will try to keep my answer simple.

Lets consider an example, suppose you have 1 Kg of raw material for baking cakes. You can either make two cakes of 500 grams each of 4 cakes of 250 grams each, or at max 5 cakes of 200 grams each.

You want to make many cakes as you don't know which cake customer will like. Let's keep the sales price of cake as $100 per Kg, assuming the cost of cake to be $60. That gives you $40 profit on total sales.

The more cakes you bake, more efforts you have to put in, there may be a case that you end up spoiling all the cakes as you may not be able to focus.

Case 1: Suppose you made 5 cakes of 200 grams and customer liked 2. You will get $20 per cake, that equals to $40 total. You will end up with a loss of $20.

Case 2: You made 2 cakes, customer liked only one, you get $50 bearing a loss of $10.

Case 3: You made only one cake, you focused and devoted all your time in making it best. Customer bought it for $100 fetching you $40 profit.

In each case reward is linked with risk. I would recommend you to execute only one idea at a time. You can filter out all the ideas and choose the best, then execute it. Believe in yourself and take risk. Even if it fails, it will give you a lot of ground for the next idea.

All the best.