Small room bass: plain wall vs closed window?

Hi all!

I will move to a new very small room in my new house, and it currently has no windows, its all perforated brick walls. The room measures 3 x 4,25 x 2,80m (WxLxH)

I have the option to open a window in one of the side (long) walls, and then close it back up with drywall, or just leave it plain brick. (this way the room would have a window already in case I stop working there. I will do some work on the house before moving in and putting this window now would be cheaper and more convenient.)

I'm torn between the two scenarios because:

1. I think this can cause an imbalance in LF response between L and R, as the wall on my right will be much more flexible and lower mass than on my left.

2. I think that having a bit of more flexible wall such as drywall can do wonders to controlling bass in such a small room. I worked in a 3x3x3m room for I while that I treated to +-5dB down to 24hz, and believe the drywall on the window helped a lot with that.

So, without being able to measure anything before deciding on this issue, what do you think I should do?

I am planning on putting 60cm deep fluffy fiberglass on all surfaces, covering all walls and the ceiling.

Thank you for your help!