OP you are right in that, for an ordinary person with an ordinary amount of time on their hands and not living next to a market/alternative shop, escaping lots of plastic can be an issue.
However, there are a few little steps you can take.
You mentioned loo paper - buy the huge packs rather tha lots of little ones and you have cut your plastic use by half with a much smaller surface area : volume. Same goes for other plastic-wrapped stuff.
Buy only what you need and nothing 'just in case'.
On plastic containers, re-use what you can. We save plastic boxes from take-aways to store our leftovers in for freezing. We re-use bottles until they fall apart. Most plastic toys for my child are hand-me-downs. Most of their clothes are. I rarely throw clothes away - they either go to charity shops, get used to clean with or get sewn into something else (currently a patchwork blanket). We re-use bags until they can no longer be repaired.
We rarely buy anything for crafting. I save whatever plastic boxes and containers I can for that and visiting children love it.
If you look at microplastics, many of them come from tyre erosion, so driving less cuts plastic waste. As does using make-up without glitter and shine.
You can do so much without changing your entire lifestyle. Some here go to extremes and that is okay if it works for them. But for many, a life like that is not practical, so a bit of common sense helps cut down your use to a more reasonable level.