One of the most common mistakes we see as mentors for entry/new-grad portfolios is not enough continuity between the steps outlined in a portfolio.
The purpose of doing user research in the beginning is to gather insights that inform the design process. In your case study, we want to see your new insights being reflected in outlining the problem, the choice of what techniques you want to use, and what decisions were made.
Later on, the purpose of doing usability research is to either confirm these choices work or if changes need to be made. You really want to tell a story of how the design evolved and how the research led you to the final deliverables at the very end of your case study.
Of course this is not the ONLY reason you might be passed on for interviews (especially for entry/junior roles). There are many other factors at play, but here we will focus on the concept of storytelling and continuity for a portfolio project.
I often see junior/entry-level portfolios where it feels like research is being done to tick off a box, but the insight is just kind of dumped and forgotten. Sometimes there is no explanation of how the final deliverables even link back to the original goals.
This "formulaic" approach to portfolio case studies is examined in detail in this article, highlighting the problems found in many "bootcamp-styled" case studies often found in junior portfolios.
It is not about just doing a customer journey map, making personas, sketches, lo-fi, high-fi. Those are all just steps that facilitate the process. You want to weave the narrative with the results of doing all those steps and explain how they affect the next step you take.
You might look at the portfolio of someone in a similar position as yourself who was successful in landing a great job and think "mine looks so similar.. I also identify a problem, do personas, show some sketches, etc." but the difference will likely be in how well their study flows and connects. And that is something that hiring managers notice.