In one investor conference, I remembered presentor mentioned that when Markowitz was asked about how he decide asset allocation? Answer: I divide avaiable investment amount with number of assets class (e.g. equity, real estate, bond, bullion aggergating to 4) and do equal allocation to all available asset class. So while it look very fency to use these model, over a period, many professional and innovator himself (if the incidence cited is facutally correct) found it not pursuing in real life.

By no means, I want to discourage you in your learning. We all need to understand theory, limitation and try to apply in context of our objective and environment. Just wanted to highlight real life difficulty in applying theory to practice. Appreciate your effort and wish you all the best for future.

Enclosing link of article which cover above aspect
“# The Unheralded Contributions of Markowitz to Behavioral Portfolio Theory

“I split my contributions 50/50 between bonds and equities,” Harry Markowitz said in a famous 1998 interview with Jason Zweig.¹ Markowitz readily admitted that he did not compute co-variances and draw a mean-variance efficient frontier. “Instead, I visualized my grief if the stock market went way up and I wasn’t in it — or if it went way down and I was completely in it. My intention was to minimize my future regret.”

Many have interpreted Markowitz’s words as implying no benefit in pushing portfolios up to the mean-variance efficient frontier. This interpretation is incorrect. To me, however, Markowitz’s most important words are, “My intention was to minimize my future regret.”

I met Markowitz for the first time at a 1995 conference and shared lunch and conversation with him. He has been my mentor, co-author and friend ever since, and I remain grateful to him now that he has passed away almost 30 years later.

Markowitz was justly proud of the mean-variance portfolio theory he offered in 1952.² That theory earned him his share of the 1990 Nobel Prize in economics and remains a foundational block of modern portfolio theory, also known as standard finance, or what I call finance for rational investors.

Two portfolio variables determine the mean-variance efficient frontier, a portfolio’s expected return and its risk, measured as the standard deviation of the portfolio’s returns. The efficient frontier comprises the portfolios with the highest expected return for each given risk or the lowest risk for each given expected return.”
https://www.avantisinvestors.com/avantis-insights/markowitz-behavioral-portfolio-theory/