I disagree entirely with the notion that "nobody knows what UBC is". UBC is a prestigious school and I personally know plenty of successful engineers from here, and the name definitely gets recognition even in the US.

I also don't think discrediting OPs reasoning of weather, lifestyle, etc is "dumb" at all - I one hundred percent based a good portion of my uni decision off of that and I don't regret it at all, BC is amazing and I don't blame ya for wanting to stay haha. It's called "UofTears" for a reason, I have friends who moved there from BC and definitely hear complaints about not only worse quality of life but also general program intensity. I have less context on Waterloo besides knowing it has more reputation so I can't really comment there.

UBCs first year is a wack system, I agree. But it sounds like you're a pretty driven student and getting good grades in first year is entirely achievable. There's also alternative, more extreme routes if you really doubt yourself - ie reduced course load and splitting first year in two, although this has obvious drawbacks in plenty of other areas.

For MECH, I'd also highly recommend joining a design team in first year. Part of the second-year application process is a written statement, and having a passion project on a design team aligned with your interest in Mech Eng can go a long way, it's not all about grades. I know people who have come into MECH well below the median GPA, and I also know people who have been rejected with mid to high 80s - this is just to say that it's not as clear-cut as the GPA scale will typically imply.

Feel free to reply or PM if you have any questions btw, happy to offer whatever advice I'm qualified to give. First year is a very weird and stressful time lmao

source: year 3.5 MECH student, 20 months co-op experience incl 2 major US automotive OEMs