Is it it bad to become a part-time student in my 4th year and do a 5th year in my undergrad if i plan on applying for grad school? I'm currently a 4th-year student at a university in Ontario, Canada. Due to covid starting last year, I realized I wanted to pursue a master's after my undergrad and planned out the courses I would need. I didn't have many of the prerequisite courses needed for the master's and had too many courses required for my degree left, so I decided I'll do the 5th year (at the beginning of 4th year, I still had 6 courses required for my degree as well as 6 courses required as prereqs for the masters, and many of the prereqs are also prereqs for each other so I would have to do at least 2 extra semesters of school). Sorry, that may sound a little confusing.
Now, also due to covid I realized online school and learning through zoom was not helping my case, and I ended up dropping some courses and becoming a part-time student for this year. Due to needing the prereq courses for the master's program I hope to apply to, I ended up needing to complete 4 courses over the summer of 2020, and as of March 2021, I have been in school every semester since September 2019 and began feeling very burnt out. I decided for my mental health and to get better marks in the courses that were necessary for me to complete, it would be a better idea to go part-time.
My question is this: do grad schools view part-time studies like this negatively? I want to pursue a master's in Business/Management Analytics, hopefully in Ontario. I reached out to a couple schools who are my top picks, and they told me they have no problem with part-time studies, they just want applicants to have at least a B+/A- GPA in their final 2 years of school.
I recently dropped a course that was focused on Business Analytics because I felt very out of my depth. The course covered topics in Stats and Probability (courses I will be taking in my 5th year because I am completing the prerequisites required for them rn) and I felt extremely lost and did terrible on the midterm. The prof wasn't much help because he treated me like I was dumb when I didn't quickly understand the ideas of things like Support Vector Machines and Neural Networks (topics I'd never covered in the past). I've been beating myself up over this decision for a couple days now because I feel like I gave up on a course that introduces me to many things I planned on doing in my Master's, but I felt it was the best decision for my GPA and overall mental health.
Are the decisions I'm making good? I feel fed-up with school right now and feel like the good marks I've gotten are only because of my reduced course-load. I feel like a couple years down the line, I won't regret my decisions. But right now, it feels like I'm taking the easy way out when the harder route would result in a horrible GPA.
It seems from`

I reached out to a couple schools who are my top picks, and they told
me they have no problem with part-time studies,

that you've answered your own question.  Besides, you can't change the past, but only the future.  Therefore, my advice is to stop &quot;beating yourself up&quot;.  School can be difficult at the best of times, and things have certainly been hard during this past year of covid.
At one point in your question you talk about classes that you found challenging because of your background.  So, if those classes will be important to your future, it might make sense to do some independent reading on the topics that are causing you troubles.  Sometimes, revisiting something can make a world of difference.
Things have a way of working out.  Be sure to reach out to people in person, as well as over the internet.  You may find that a lot of successful people have also faced challenges.  Knowing that can help a lot in getting past hurdles.
Spring is coming.  So is vaccine. Things will start to get back to normal soon.  You've got years ahead of you.  Don't worry too much about the exact school you get into.  Find a spot that you think you'll enjoy, and plan to enjoy it and learn a lot.  Sometimes, just making the choice to enjoy something (even with challenges) can make a big difference.
Good luck.