As you know, Quebec decided to be more restrictive than other provinces with the SQDC-only retail stores. Have you tried watching the reddit r/SQDC?
Are there any brands that I should look for in the shops with a higher chance than the rest of being great quality?The shops are hit or miss. Quality in general is meh, every now and then you can find something good though.
Small topshelf growers are somewhat rare. Most will grow commercial flowers, or straight up mail order pounds of greenhouse mids.