"Winter" gas a higher Reid vapor pressure than "summer" gas to help it ignite in lower temperatures. Reid vapor pressure can be changed by the addition or removal butane (along with many other different additives). Gov.gc.ca doesn't specify a mixture ratio that I can find. As for deteriorating emission equipment, could be a cash grab among other things.
"Gas mandates", Why do you thing that pumps are showing a higher ethanol content or the removal of 94 octane. Its not like people weren't buying it before. Presumably it goes though nrcan.gc.ca for mixture ratios/blends and its likely different between regions in Canada. It would be weird to assume that gas stations in Merritt and Hope at roughly 4000 ft above sea level would be able to sell the same gas as they sell in Vancouver exactly at sea level, or comparing gas in Colorado (~5200 ft) to gas sold in Ohio (~800ft). Assuming all based on Boyle's Law P1V1 = P2V2
Speaking of cash grabs, "oh no, we've stopped importing Russian oil. Time to raise prices"
https://www.canada.ca/en/natural-resources-canada/news/2022/02/government-of-canada-moves-to-prohibit-import-of-russian-oil.html
Canada banned CRUDE oil imports in 2019, To this day we are still importing REFINDED oil from Russian. Atlantic Canada is one of the biggest Canadian users of Russian and "other" imported oil. Nothing has changed since 2019. (Unless they have changed that very recently)
https://www.cer-rec.gc.ca/en/data-analysis/energy-markets/market-snapshots/2021/market-snapshot-crude-oil-imports-decreased-in-2020-and-so-did-the-cost.html
The "other" category looks a bit suspect, although this is strictly for Crude oil imports and not refined.
TL;DR
Why are we getting charged more for natural gas, gas, diesel, ect. - Because reasons
What I likely think the culprit is in this case; They're adding additional "sin" taxes to deter the sale/use similar to tobacco/alcohol.
But that's not an opinion on if this is right/wrong