It's possible to merge or delete accounts?

Hello. I have a small problem.
I recently discovered that I have created three accounts.

1.SergeiZ, 9/20/2021

2. SergeiZhilinski (this), 9/21/2021

3. SZ, 9/22/2021

Based by the activity and creation dates, I created them on different computers due to the fact that I could not remember what email the previous account was created on.

Today, through simple tests, I was able to establish the email to which each of these three accounts is registered (just sent a private message and check which email the notification was sent to).

Actually, my question is this: is it possible to somehow merge all three accounts into one or delete two extra ones  (better to save SZ and delete SergeiZhilinski and SergeiZ)?