Most government or government-adjacent (sépaq, Hydro Québec) websites are pretty decent. There's a few awful exceptions like the SAAQ disabling their online services at 11pm, as if their servers need to go to bed? Or the city of Longueuil's tax portal which looks like it is from the 90s!
On the topic of Hydro Québec, there's just something about the scale of turning the fifth largest asteroid impact crater into a reservoir for hydroelectricity that is awe inspiring. Why don't we see those sorts of aspirational mega projects for the greater good in Canada anymore?
I think the stars have to be aligned for a project like that to work. You need buy-in from first-nations, a charismatic PM that won't get thorn apart for spending prodigious amount of money and general public goodwill towards the objective.
I interact the most with AFE (aide financière aux études) and FRQNet (grad school scholarships). These websites look like they weren't updated since about 1999 and are really, really counter-intuitive to use. Admittedly, they're also probably not the most used websites, and not high in their priority list.
Can you still catch a bus in Montreal at 26:30h? :) Used to be able to see bus schedules online for busses STM well-passed the 24h mark. Something about the technology not being ready for late-night busses on the 'next day' being attached to 'today'? Or something.
Their immigration and SAAQ sites are what I've interacted with most recently. Both "just worked" and had reasonable UI and UX without having to disable adblockers or use IE or any nonsense like that. There are small nits occasionally, but by and large they work for their intended purposes I've found.