There seem to be two issues here: (1) you're concerned about qualifying for "trader tax status," and believe that one of the criteria is to have a "trade plan"; and (2) you're wondering if your tax accountant can reverse engineer your "trade plan"/strategy from your brokerage statements. Correct?
If so...
With regard to Item (1) -- to further clarify the requirements for trader tax status, this might be helpful:
https://greentradertax.com/trader-tax-center/trader-tax-status/how-to-qualify/
You might also want to learn more about the Section 475, mark-to-market election:
https://greentradertax.com/trader-tax-center/trader-tax-status/section-475-mtm-accounting/
https://www.thetaxadviser.com/issues/2010/feb/sec475mark-to-marketelection.html
With regard to Item (2):
I am *not* a tax expert/professional, and don't know if your accountant would want to see some evidence that you qualify for trader tax status before he/she treats your taxes accordingly... but I'm definitely skeptical that anyone could reverse engineer your strategy (especially) from simply having access to the brokerage statements that a tax accountant would need to do your taxes properly. Even if they could, then that would lead one to question how proprietary/unique/complex (and profitable, lol!) such a strategy would be... and therefore whether it'd be worth his/her time & effort to attempt that.
If you're concerned about your tax accountant ever demanding to see your actual "trading plan," in addition to your brokerage statements -- I don't see how he/she could justify that based on the requirements for trader tax status that I'm familiar with. My *guess* is that the other criteria -- e.g., trading activity, trading income relative to any other sources, etc. would be more important if your trader tax status is ever required to be proven to either your accountant or the IRS.