If you have any memberships (eg CAA, govt), try using those. I travel to YVR frequently and can usually get a government rate at a Marriott or IHG hotel if I check back a few times. Given they own probably half the hotels in town, it only takes two searches to find out. When it’s really busy, for what it is worth, I find the Marriott Residence Inn on Hornby St and the Holiday Inn on Howe St most readily available.