Notionals as fundamental catalysts? True or not?

REPOST: shitty spelling lol sorry

Could someone give me a quick ELI5 on how options notionals can act as a fundamental catalyst for price action? Maybe this is outlined in some respurce somewhere but given that many people like to track and report on this, I figure it's easier to hear it from them.

My understanding is that options, as a derivative asset/instrument, can only serve to reveal trader sentiment, since options trades dont actually reflect in shares/volume, them being a derivative asset and all, UNLESS a contract gets exercised. Ofc, \that\ event would translate into real volume, but I'd heard somewhere a while back during the SPY rally that the ATH for call notionals was a catalyst, and sure enough that day was MADLY bullish; I just don't understand the notion- is it smart money with large size?

In continuation, another thing I think I've noticed, is that when the market stalls at certain levels following such excersicions/assignments, that price stalling is directly caused by institutional volume, being forced to buy/sell at that level, thereby flipping the trend whenever they have to bail. However, I know for a fact that the former doesn't NECESSARILY necessitate the latter, from what I've gathered. Notionals don't NECESSARILY govern price action, and yet, the options market and \\\its\\\ volume has yet still become one of the most predominant driving forces in price action, irrespective of the money-ness of the notionals. This much is evident in that "call walls" and "put walls" as seen in options volume, do in fact reflect in intraday price action, where price will just stall at certain levels for seemingly no reason. How does this work? Are there gaps in my knowledge here?

Hoping to open up a general discussion on, well ig, the notion of notionals as a fundamental catalyst. Do yall think thats true or not? Otherwise, I'm open to being directed to whatever relevant resources that are already known otherwise. Cheers