Another make work scheme which is part of the endless thirst for useless unreliable data.

Ideal if you want to stick a veneer of "caring" over your business, but really serves no useful purpose in the end.

I have been surveyed many times in multiple organisations, and the overwhelming majority added no lasting value whatsoever (including an industry-wide one that I ran for our business).

Pitfalls I have seen are:
Not getting the initial questions right, which result in a series of "What did you mean by......?" meetings (according to surveys 6 out of 7 dwarves aren't 'Happy').
Not following up on promises or actions, which makes staff distrust any subsequent surveys.
Only doing a single survey, so that any trends are not visible - we obviously look for improvement to justify the effort, but also need to know what to stop when things trend down!.

What are you hoping to achieve in a survey?
What definition of wellbeing are you using eg. 'soft and fluffy, yoga and fruitboxes', or 'the opposite of harm'.

A way to fix the worker so they are more 'resilient' so that they will take more %$#& and do more work.
A way to work out why people only last a year before finding another business to work for (as soon as they are fully trained and functional in the role)
A way to see if the jobs match the training match the time available match the management/leadership style match the output required
A way to see if the business concentrates on 'ambulance at the bottom of the cliff' rather than make the work work better
A way to unpack toxicity and the 'ism's so that people like being at work and like the people they work with
A way to make the workplace mentally safe and healthy as well as physically safe and healthy

Like virtually all surveys, the value of the responses relies heavily on the quality of the survey questions. It can be too easy to ask questions designed largely to get the desired response, rather than finding out anything meaningful about wellbeing. If the questions are designed by someone who is knowledgeable and skilled with elements such as the choice of words and framing of the question, it might be possible to get sensible answers that genuinely provide meaningful insights. But if management doesn't have clarity about what wellbeing looks like in their organisation or what they want their culture and employee engagement to look like, it's unlikely that managers would even know what questions to ask.