Dear Founders:
Do you remember how you made your first friend at kindergarten? Did you say "Hi, my name is John, can I play with you?" or did you just walk up to another kid and start playing in parallel?
Now, forget the costly McKinsey consultants told you about breaking the silo, which is common sense. They're very good at contradicting themselves because the same consultant would have also said to you that you should reduce cost, so you can afford to pay them.
What's needed is to have people play in parallel. In this case, playing could be development, playing could be project management, playing could be product management, playing could be operations, playing could be business planning, and playing could be security.
If an 8-year-old child can learn Python, do you think a project/product manager cannot do a bit of programming? If everyone knows addition, subtraction, multiplication, and division, do you think a SOC analyst cannot write a TAM/SAM business plan? If a baby already has cliff-detection built-in (yes, look it up, it's a published research), do you insist that security incidents must be led by security instead of anyone else? Heck, the most significant impact of any incident is the business revenue.
These incidents should be really be led by the revenue teams. I once told a founder, pick the person who's getting shouted at by the customer to lead the incident response. Are you telling me that the sales just go to sleep after almost-always mis-selling the product and the operations team is taking the heat while the sales sleep? Remember, the operations team might get woken up at night, but they don't have any financial impact, the company revenue might get a nosedive from the incident!
Once people play together, they become friends. What silo?
My last piece of advice is to make more of you, the founders, who can play all the above, instead of building teams who can only do one of each.