There is no doubt that these grounding boxes have an effect. The real question...is the effect beneficial ?
For example...slightly tipped up sound at the expense of sound in other frequency ranges (low to mid bass) giving the illusion of more resolution...
I have my Entreq boxes out of the system now and am starting to seriously consider selling them. Still haven't decided. I now firmly believe it is possible to over tweak one's system (footers and grounding boxes)...a real rabbit hole one can get lost in and so too, the ultimate sound potential of the system can be lost via over tweaking. YMMV.
Your room seems a bit small to really be able to gorge yourself on the hightened spatial information. I personally think they're anti timbre & texture, which are more important to me than a massive soundstage.
$ is best spent on the big ticket items... which are the most costly to change so I can see why people like "tweaks".