you may want to read this thread
https://www.investopedia.com/ask/answers/09/mutual-fund-etf.asp#:~:text=Mutual%20funds%20have%20more...
note that one line in the key takeaways says
Mutual funds are actively managed, and ETFs are passively managed investment options.
while lower in the thread
In 2008, the Securities and Exchange Commission (SEC) streamlined its approval process for ETFs, which for the first time allowed for actively managed ETFs.
how they are managed is something that the IRS could take into consideration in determining whether the two securities are substantially identical.
