Hello.
It's a fascinating topic for me also. I am almost sure I have ADHD, but for our country, it is still an unapproachable area, especially for adults.

I was interested after your post and found some articles related to this - Inner Monologue in ADHD

"Not Exclusive to ADHD: The idea that having an internal monologue is a sign of ADHD is oversimplified. An internal monologue, or the experience of having an ongoing conversation with oneself in one's mind, is common among many individuals regardless of whether they have ADHD. Research indicates that about 30-50% of people regularly experience internal monologues, which can serve various functions in cognitive processes like planning, problem-solving, and memory processing. However, the nature of the monologue might differ; for some with ADHD, it can be more distracting or hyperactive, but this isn't a definitive diagnostic criterion."

Also this:
"The idea that being more productive around others suggests ADHD can be misleading. People with ADHD might find it easier to focus in a structured environment or when there's external stimulation, but this isn't exclusive to ADHD. Many people find they work better in social or collaborative settings."

Stimulant Medications for ADHD Treatment: Types, Side Effects, and More
"Stimulant medications like Adderall or Ritalin are commonly used to treat ADHD. The fact that you responded to stimulants by feeling calmer or even sleepy isn't uncommon in individuals with ADHD. However, this response alone doesn't definitively confirm the diagnosis."
My reaction to amphetamine was a full relaxation. But only 2 times - on the third, I started to talk and was very active.