My Grandmother was born in the UK in 1940 (I have a copy of her birth cert).

Her daughter, my mother, was born in Toronto, Canada in 1960 but due to women not being able to pass on Uk citizenship at the time, my mother never received it (still doesn't have it).

I was born in Toronto, Canada in 1985.

From what I'm reading, I have a route to citizenship due to “historical legislative unfairness” and the law change. My mother wouldn't have been allowed to register me via the consulate, as she wasn't a "father". There are people who also say it's not possible because Canada didn't allow Consulate registration at the time, but I'm seeing many people posting they were born in Canada in my exact scenario successfully getting citizenship via 4L.

Any insight?

Folks are correct consular registration wasn't a thing in commonwealth countries so while your mom has a claim you do not. That said I have seen one positive data point of a 4L clam made on consular registration from Canada reported on Reddit. If you are wiling to throw some time and money at an attempt go for it but technically it shouldn't be approved. I would say it is going to be YMMV at very least.

You don’t have a claim unfortunately, unless your mother spent at least three consecutive years in the UK before you were born, but as a Commonwealth citizen with a UK-born grandparent then you are eligible for a UK Ancestry visa if you wish to live and work in the UK. This would put you on a 5-6 year path to settlement and naturalisation as a British citizen.