First we have to convince people that they will be better off if they have to pay a lot more for their toy trucks. That is the step 0 that nobody seems to know how to solve. Hollering about how the oil company CEOs are evil is not going to be the thing. It's already been tried. People will nod right along until you get to, "and that's why your gasoline needs to cost $7/gallon."
Trucks are 3.4% of US GHG (~60m trucks at 3.51 megatons CO2/yr is ~211 megatons CO2/yr out of 6,266 megatons from the US total). If we never started another pickup truck ever again we're still 96.6% away from zero emissions. It's also worth saying those people would probably still drive something and the odds of that car being zero emissions is very low, so this is pretty charitable. Anyway, this kind of finger wagging--bordering on contempt--is exactly why this has become a political issue. These are collective action problems. We're not going to solve them by asking/forcing people to take tremendous individual losses, no matter how repugnant you think their way of life is.
Trucks are just an illustrative point. Substitute for whatever trivial thing it is that people like and would not be willing to give up. {Beef, air travel, fast fashion, 69 degree interiors during the summer, etc.} Each one of these things only contributes a little on their own but if you add them all up it sums to a large fraction of overall US emissions.
Also not sure where you got the 3.7% number, but light duty trucks overall contribute around 10.4%. This includes some fraction of SUVs (those with truck-like drive trains weighing over 6000 pounds GVW) and minivans.
That being said, decarbonization of the truly necessary energy consumption is also a requirement, and that is expensive too. You need to convince people that they should want to pay for it -- no the billionaires cannot pay for the whole thing, for inflation-related reasons that are too complicated to get into right now. (The basic thrust of the argument is that US construction and industrial capacity is already highly utilized, and that allocating more workers to decarbonizing will necessarily drive up the cost of everything else, regardless of who nominally pays for the work.)
69F interiors would be no problem if powered by solar. The government massively subsidizes oil, it could have been subsidizing solar for decades instead but didn't because of how powerful and profitable the oil industry is.
Nobody gives a shit how the factory that made their toy was powered. Top-down approach forcing industrial changes could nearly solve the whole problem without individuals needing to change much of anything.
But entrenched interests will propagandize and say "the hippie whackos think you shouldn't be allowed AC" (like you kinda seem to be doing, frankly) when that isn't and never has been the only option.
