Trust me, as someone who just filed 10 years of returns on behalf of a deceased person, for the amount of time you would spend trying to locate and access a software that can do it (spoiler: it exists but is expensive), you would be better off just diving in to the paper version yourself. This will be true regardless of the complexity of your return.

A basic return includes a provincial schedule, a federal schedule, and the T1 itself. Anything else required, e.g. taxable gains or foreign income, just work through it one at a time and follow the guide for that schedule and year. Use the worksheets. Compile and organize your backup documents (tax slips, etc). Call CRA if you come across something that you can't figure out by reading. You can use a free spreadsheet to check your calculations and the fillable PDF forms. There are probably some tutorials online. It is totally worth doing it yourself purely for the benefit of learning how.