It would not be considered poor work ethic to work part time in your main role whilst studying. Gaining relevant experience alongside is a positive thing to do. Most employer are asking where you worked, what you did and any significant achievements. The physical time spent doing it is less important, so long as you can demonstrate the skills gained on demand. On you CV, you do not have to specify whether the role was part time or full time. Application forms may be more specific, but in the current climate many people are employed on a part time basis.
The key thing is to ensure you allow enough time to complete your studies well. Sometimes it is not time spent, it is the quality and focus that affects your final mark. So make sure you get feedback on where you went wrong on your initial assignments. Do not be afraid to ask for help to improve the quality of your work. Transitioning from work to study can be a bit of a culture shock as at work the metrics are less nuanced, either the task got done or it didn't, whilst study is a scale of how well it was done.