Store a backup on a USB stick you keep in your house (in another room than your computer)
A sentence is easier to remember than random letters and it's length and punctuation make it stronger than most pw. Use a sentence you like from a book, a video game, a show or a music. It's easier to memorize and bring a bit joy when you type your own.
It maybe work less on you but it probably still work well on you. Advertisement isn't as much about product anymore, it's about brand. A logo seems innofensive but shown enough it become more familiar to you increasing the chance you choose this brand when you buy a product.
Another type of ad is the "cool people do this" kind with the objective to create a need and make you buy a product of this type. Even if you don't choose the brand that advertised it you still enter the market. If you care less about the judgement of other this kind of ad probably work less, if you're desperate for bonds maybe it work better so I don't really know how different it can be among autistics.
In any case my advice would be to not let your guard down, that's exactly what the seller want. Use an adblocker, mute the tv during adds, don't look at the advertising poster when you walk or drive outside. You could even talk about this to your mayor.