For those who don't know, a fiduciary is legally obligated to work in your best financial interests, so it's pretty important that your financial advisor is one.
Reinforcing this, someone with constrained by fiduciary duty must make (and be able to show) recommendations/actions based on your best interests when it comes to your money or be liable.
An adviser that is not operating under the duty, can place their best interests above yours legally (and this is expected).