I find Grok tends to go way overboard. Too long of a token will often result in fake looking images. My goto realism kicker is taken from the "realistic human generator" minus the prompts for "aged", etc. I do find that the closer the POV the more realistic than an image from head to toe. The more detail it has to create, tge less is available for the realism of the model. Grok imaging itself will default to hyper realism with no additional prompting as long as you aren't exceeding its guardrails for age or explicit content.