Since I did not update it here, I thought I should. Anyways, long story short – the stabilizer did not solve the flickering issue.
It appears the problem is with some interference with something not related to the usual flickering which can be resolved with a stabilizer. I am not sure if the 5m long HDMI cable that passes through the wall is causing it. If I were to connect the regular Dell display with the PC, there are no such issues. I shall check with a shorter HDMI cable if it resolves the issue.
Anyways, the stabilizer should be up for sale on the market section shortly. It has been lying idle for almost a couple of months now!