I’ve also heard Abhidhamma teachers say that samatha is impossible And yet somehow people get enlightened anyway!
So, in my opinion, just ignore the haters and focus on what you can feel: the breath, the body, sensations, etc. Eventually, if your samādhi gets good enough, you’ll start to perceive the more subtle workings of consciousness for yourself.
At that point, thinking “was that bhavanga?” will just be a hindrance. So, if you have to label those feeings when you get there, “pleasant,” “painful,” or “neutral” will suffice, as the satipaṭṭhāna sutta recommends.
Namely, when bhavanga is seen and recognized, it’s felt as a kind of terrifying, existential feeling (“knowledge and vision of the way things are”) which eventually (if you keep going) will drive the mind towards revulsion, dispassion, letting go and release from the viññana cycle.
Then, once you’re enlightened, there will be plenty of time (and personal experience!) to geek out on the Abhidhamma! Until then, my opinion is to stick to the suttas and whatever meditation objects you can feel
Like (personal confession time), I have never been able to identify the 7 enlightenment factors in my own mind. Perhaps because I don’t have any of them Or perhaps because I am still not confident I can identify them accurately. For whatever reason, mindfulness of the enlightenment factors has yet to be a useful satipaṭṭhāna for me. Thankfully there are plenty of others, such as mindfulness of the bodily postures or of the five hindrances, which I can confidently identify as they happen. So I just stick to those and if ever I get a good sense of the enlightenment factors (and get any of them!) then maybe I’ll be mindful of them… but until then… “sitting, typing, …” Hope that helps