I'm curious. Did you read what I wrote or watch the video or did you simply read the title? I ask because you go on and on about bass traps but I actually don't mention a single bass trap in my post, aside from the tittle.
Helmholtz resonators are not bass traps. They do not trap the sound. They are also not snake oil as they have been used for millennia to tame sound in large churches and such in ancient days. They are used today to help tamp down the sound from our exhaust in our cars.
I have since made 6 more of these for a total of 12 in my room and they definitely brought some of the decay time down at the frequency they were tuned at.
I read it even twice...
Bass traps are Helmholz resonators, as far as I can see. The things you see in churches are organ pipes. They work because they produce resonances, but you can not get the resonance back inside...
Anything else will not take up energy at all. Anyway, with your two measurements I see nothing that may not be the cause of two measurements, some time appart. Repeat them 15 times and average them. Do not touch the microfone, do not change your position. Even the simple existance of a larg object in a room or an open door will cause differences like you see in your plots. Even the software induces differences.
Even if you change nothing in the room, there are always measuring tollerances of a few dB. Try it.
In most cases what you belive to hear is what you would like to hear. You think it will work, otherwise you would not wast time and money for this "experiment". So you are subjective and fool your self.
I have been to audio trials, where the charismatic instructor could convince a majority of listeners of audible differences, even when nothing was changed at all. If you objected, others would comment like "wash your ears" or "get a hearing aid". The harder you try to hear a difference, the more likely it is you do.
To hear a difference is good, not hearing one is disapointing. Like failing a test.
I for example, have very simple, cheap A-B switching devices. Remote controlled, the last build even wireless, so you don't have to move your body for an objective A-B comparison. I use to it to compare amplifiers, CD player and DAC's, and while improving speakers
Such a device should be the minimum hardware for anyone who has an opinnion about any gear. Not many posting here have something like that. I add a picture of mine.
Decades ago I had to realize that recognizing small differences by listening was impossible if you had to get up, switch some gear and change some wires. Like when you wanted to know which type of capacitor sounded better in a crossover or even a RCA cable. With a break of only 30 seconds, things got inconclusive. If there is a 5db peak in the midrange instead of a flat, you can easily hear it if you hit the note, same with 2% distortion to 0.1%.
Anyway, when you start to fine tune things, your audio memory is very,very limited and dependent on your personal mode, concentration, time of day and outside noise.
Always try to stay on a foundation of physics.