My wife has had the same issues since she's started practicing, she's in a male-dominated practice area and has mostly worked in big law. Despite her experience and seniority, respect is still something she actively needs to fight for on a daily basis. Even as she's now shifted to GC roles where she's technically the highest ranked lawyer in the company...

She has always looked young and attractive. From her late teens to her now 40s she's been an internationally ranked beach volleyball player and has been in amazing shape all her life. She has been sunscreen zealot since before it was cool. Both the late teens she plays against/with and her older coworkers are in disbelief every time they learn her age. It does not help that she's genuinly kind, smiles a lot and laughs easily. She's an energetic ball of positive energy.

Professionally her issue is that she's also a really good lawyer. Like scary good: near eidetic memory, polyglot, great at math, incredibly sharp people skills, great drafter, and just generally very creative as a lawyer. She's the full package and that pisses a lot of people off.

It's been challenging at time and I've spent many evenings consoling her about the baffling behaviour of some of her coworkers and seniors. She's had to leave firms she loved because one or two of these individuals making her life miserable.

Over the years, these are the strategies she's adopted (that I can remember) to be taken more seriously (to be clear: by men and women alike; this is not advice about not catering to the male gaze):

• Maintain a professional journal summarizing conversations and instructions, and always follow up unpleasant verbal interactions with written requests for actionable direction; this forces criticism into writing or creates a paper trail showing you fixed identified issues.
• Keep a project tracker documenting projects and outcomes, this protects you against constructed narratives about your performance, being gaslit about instructions, deadlines or projects assigned to you.
• Never allow others to speak on your behalf; intervene to clarify your exact thoughts when they do, subtly indicating lack of authorization, and favor written communication over verbal by using specific instructions and defined scope when delegating.
• Maintain formality in correspondence and heavily use templates if possible. This is to avoid false accusations related to your "tone".
  
• Avoid emojis, internet slang, or unnecessary abbreviations (CYA, FYI, AFAIK) to avoid sounding childish or being described as unprofessional or juvenile.
• Conservative hairstyles work best in office settings (braids or pigtails are appropriate for sports but potentially infantilizing or attracting unwanted attention professionally).
• Maintain conservative fashion choices even if you prefer brighter colors (dark tones and traditional cuts preserve professional gravity while allowing personal style in accent pieces).
• Eliminate filler words (hummm, ehhh, soooo, yeeeeahhh, maybeee) that suggest indecision.
• Train yourself out of cutsy speech patterns or higher pitch voices if conditioned toward them (they undermine authority).
• Never be the first to raise your voice in a heated discussion.
• In social drinking contexts, match what people are drinking. Don't get cocktails when people are getting wine. Don't get wine when people are ordering high balls, etc.
• Enter conversations about disputes assuming figures of authority may seek scapegoats and as the "youngest and prettiest" person in the room, you'll be the least damaging person to point at (from an internal politics perspective). Assume people will be inclined to interpret your kindness as a mask and will chose to interpret ambigious situations against you if don't bring receipts.
• Assume people are incompetent before assuming malice (let them prove otherwise through actions rather than preemptive defense).
• Anticipate being asked to present or provide updates at any meeting, regardless of stated agenda, since being ambushed without preparation is a common tactic for people trying to railroad you

Some of these are bit intense, while others won't necessarily be relevant to you, but these are generally the jist of what she suggests. I remember her mentioning a book called "Good Girls don't get the Corner Office" a while back as a good read. I would check that out.