Reckless, yeah okay...
In my experience, the only time serum estradiol levels can be singularly conclusive is when someone is natural, or running true TRT. As soon as you get into supratherapeutic doses of exogenous testosterone, the numbers are simply one of many objective/subjective variables that need to be considered.
Over the years, I've learned that things such as A:E (androgen:estrogen) ratios are FAR more important as it relates to someones potential for developing sides and/or feeling less than ideal. And, when we start talking about someone using more than just testosterone, then serum estradiol becomes even LESS valuable as it relates to a singular test metric.
Not to mention, that you now have the entire progresterone/prolactin/estradiol axis, so even if estradiol "is in range" that does not mean that someone is actually where they should be hormonally.
Now, don't get me wrong - I still have all my athletes get a set of comprehensive bloods done after each contest (or blast) because I'm a huge nerd when it comes to data and seeing what the body is doing under the hood. But there are just so many other objective and subjective variables to consider than thinking you can look at test/estradiol numbers and have a full picture is just silly. And yes, some of this will be subjective as I've had a number of folks come to me with "issues" and to the casual observer their tests all showed values in range...so what do you do in that case?
I take a lot of pride in the fact that most all of my athletes who came to me relying upon AIs and ancillaries have either stopped using them altogether or significantly lowered their reliance upon them over time....