That pattern is the main line, not the fixtures. One slow sink is that sink's trap or branch; every drain slow together, with a toilet gurgling when the washer drains, means the restriction sits where all of them meet. Stop running water where you can, because the next stage is backup at the lowest fixture, and call today. Main line clearing runs $200 to $500 in published guides, and what the cable brings back (roots, grease, scale) decides whether a camera should follow.
Prefer to talk later? Leave your details and an independent local pro will call you back. No charge to you, no obligation.
Westridge Plumbing is a free referral service. Submitting this form connects you with independent local contractors who provide the work.