By “the rule” I assume you mean one of the criteria cited in the 2012 Kreisschreiben about potentially being classified as a professional trader if selling securities held for less than 6 months?
I discussed this as recently as this week with a very seasoned colleague of mine whose father happened to be a tax advisor for many decades.
According to this colleague, the Steuerkommissär looks at the collective of your activities to decide whether this is a self-employed task/activity to generate income. The Steuerkommissär will use the criteria cited but its at their discretion to come to a conclusion from an overall impression.
This colleague also guesses that an occational violation of a criteria will be tolerated as long as it’s not evident that you are trying to create income with a violation … and as long as the Steuerkommissär doesn’t have a bad day. 
This colleague also knows from his father, the tax advisor, that most Steuerkommissäre can be reasoned with.
If still in doubt I would recommend that you talk to the tax authority person handling your taxes (they’re either listed on your previous tax bill or you can call the tax authority and they’ll connect you with “your” person or will give you a direct number.
This person is not the Steuerkommissär but they will be able to give you guidance, and I’m pretty sure if they are in doubt they will doublecheck with an actual Steuerkommissär.
To add a tad of personal experience color: I was audited last year by a Steuerkommisär for my 2022 tax returns.* The Steuerkommissär looked in very much detail at all of my trading activities (trades, dividends, etc) and I know I have violated rule 5 (roughly: “derivatives, especially options, can only be used as hedges of existing positions”) as since 2020 I do Stillhaltergeschäfte (I have sold Puts both to generate income** as well as to buy stakes in companies). I do try to have only a few Puts on my year end statements to fly below the radar, but I have had short Puts that were clearly not for hedging my positions. Despite those evident violations of rule 5, the Steuerkommissär had no complaints about this.
* Most likely triggered as I (truly) forgot to declare an unverteilte Erbschaft of my wife.
** Slightly orthogonal to the question about whether this makes you a professional investor: as I have also learned very recently on a different thread on this forum, by selling Puts I have not generated income, I’ve only made capital gains. Works for me.