The big problem in my eyes are trash bags. Don't know how to replace those.
Composting, and recycling glass, metal, and paper greatly reduces the need for plastic trash bags. Most of my regular trash these days is plastic that can't be recycled - either food contaminated, or thin plastic bags. And when you have so little landfill trash, you don't need to buy those massive plastic garbage bags. In my household, we just use the plastic bags that we get our produce in - and we don't even bag all of our produce, just things like leafy greens (delicate) or green beans/okra (hard to keep together)
Something like https://www.c2ccertified.org/ being applicable to every usage of plastic, essentially.
Those "flimsy" plastic bags in particular have a ~65% re-use rate in the US, whereas the heavy duty "reusable" bags often take far more plastic and energy to product, so you have to re-use them at far higher rates than the flimsy ones to make up for the cost to produce them.
40% of shoppers who have those bags forget them, so there's a world where we are actually producing more plastic and incurring food born illness from people not washing out their re-usable bags.
People not even trying to recycle is a huge pet peeve of mine, but I think the plastic bag bans tend to be kind of stupid. Nevermind that now people have to buy garbage liners instead of just re-using the bags.
https://reason.com/archives/2015/09/01/plastic-bags-are-good...
I would like to see something to get the soda industry back to aluminum, but even moving to glass the costs of it all are not very easy to track, because the significantly higher impact on energy required to move glass in bulk vs. plastic.
One good move you can make is do things like purchase bar-form soaps and shampoos for your bathroom… but ultimately we've got to get people off of K-Cups and buying so much plastic bottled water when they can just re-fill something, or bring your own container to a coffee shop.
And maybe give up on 2-day shipping from Amazon, or try to bulk-ship your order instead of placing a new one for every item you think of 30 minutes apart…
The closest solution will probably come from some kind of plastic-consuming bio engineering, or energy-harvesting incinerators like in parts of Europe and Africa: https://www.cnn.com/2018/08/21/africa/reppie-waste-to-energy...
That, and maybe move away from the "big blue bin" which has made people think they can just throw anything in there which has had the unintended consequence of causing recycling to cost much more and have way more contaminants.
Straws aren't also necessary, I don't drink coffee I buy with a straw and I'm managing fine. Soft drinks can probably just have those coffee caps and then gradually transition.