Promise.all is just a for loop that awaits all the promises. They still don't run concurrently.
The way JS works is that some event happens, which can cause some handler to run. When it's finished, the next event handler runs. But no two pieces of code execute at the same time in the same context.
The way JS works is that some event happens, which can cause some handler to run. When it's finished, the next event handler runs. But no two pieces of code execute at the same time in the same context.