One person holds the reins!
After all, every step must be correct for the overall project to succeed.
We always work under the project manager principle.
You get one contact person - both for all technical equipment-related trades and all structure design activities. He/she is your contact person and bears responsibility for the overall project from beginning to end.
The project manager represents the trades, organizes the work steps, coordinates the interaction between the systems, and tracks deadlines and costs from beginning to end.