I really understand your concern in rhyming and that is why I prefer writing in ny native language, it's easier to rhyme. Rhyming sentences in novel could create beautiful effect and emphasize if done right.
Don't be so hard as, it's your first NaNoWriMo. You won't expect by doing weekly light run, you wouldn't get tired during marathon, right? 50,000 words with consistent 1667 words per day is a massive goal and commitment, the most word I can get per day is 5000 and I sometimes struggle to create 1500-2000 word polished chapters per three day.
Think NaNoWrimo as a training camp instead of a competition with hard set rule, you'll less likely get demotivated and pressured.
I really appreciate your dedication to still think about your content quality even in an event focused only in word count. 50,000 words is not a good goal, a monkey can complete NaNoWriMo if they keeps smashing the keyboard to complete their utter shit. A good goal should be increased discipline and productivity during the event, with completing 50,000 words as a bonus goal.
Good luck!
Please take care of yourself because these kind of events is tiring and can be mentally draining or detrimental to self esteem (by comparing your progress to others).
It's not wrong to not finish or quit halfway, a yearly internet even doesn't define what kind of writer you are. There are many big writers make it without NaNoWriMo.