MCQ preparation as a limited only player

So, I have qualified for the coming MCQ by hitting high mythic in limited but I have zero experience in constructed play. I was wondering if others on this sub have been in a similar position trying to quickly catch up with constructed and could share any advice.

So far I've been practicing constructed (playing Temur adventures and Rakdos Aristocrats), but starting from Bronze 4 I'll probably only reach high Platinum before the event, so the competition is no way near what I'll face.

My thinking is that I should focus on a single deck, maybe I should go for a niche deck for a greater chance of stealing some wins as a niche deck reduces the impact of my lack of experience because the opponent has less experience against it as well.

With about a week to go and limited time on my hands, I have to ramp up as efficiently as I can, any thoughts on how to spend my time in the most efficient way?