I can't find the video now, but a couple years ago there was a science creator who broke down the overall environmental cost (co2 production, manufacturing chemicals, microplastics, etc.) of producing the materials needed to make the various bags, manufacturing, transportation, and time to break down/end of life impacts. The single use plastic bags were less impactful than any reusable bags by far. This can be increased by reusing the single use bags as you would a reusable bag before using it for garbage like you do. Only paper bags were marginally better than single use plastic, but even that is unsustainable as it is still a single use item, and produces all kinds of chemicals during the pulping process. Not to mention only ~50% get recycled, leading to more forestry to supply materials.

All that to say you're right. The 3 R's are the way to go.

My personal pet peeve are the "environmentalists" who rush out to buy new "environmentally friendly" options rather than using what they currently have until it needs to be replaced. Particularly since most of the organic replacements don't last as long. Yes, the plastic version will end up in the landfill regardless, but they could have reduced their overall impact by 5 to 500 organic whatevers in the meantime. Eco-consumerist nonsense. /rant

How much material and energy goes into making those thin plastic grocery bags?

its where they end up. They last >100 years.

I recently realised that I don't even need to use up my dwindling supply of former grocery now mostly garbage bags for smaller garbage cans around my place. Previously, I would remove the bag from the bin, tie it up and drop it in the main garbage, usually after emptying it because otherwise it would be too full (and I'm in a condo with a dumpster, so timing garbage pickups isn't an issue).

My new method is to just grab the whole smaller bin and dump the contents out into the main bin, reusing the bag unless it got destroyed since it was last emptied. My main bin is my kitchen bin, so the others are mostly getting dry things anyways. It's the adhesives that can mess up the bags now, though if it's just a piece of sticky paper, could just leave it stuck to the bag for a while if it isn't interfering with other things going in.

I've been using fancier store bags (sometimes the reusable plastic ones, sometimes the paper ones that already look like gift bags just with the store name instead of Elsa or whatever) as gift bags, mostly because buying special packaging for gifts is just a waste, especially because the kid only cares about what's on the bag until they can get at what's in the bag, then it usually sits somewhere maybe holding a bunch of gifts for a bit, probably getting ripped before it gets folded flat to be used in the future, though I'm sure some people just throw them out.