Frejlord is I think mostly canon but a bit old and not updated too much for some things (Braum, actual events other than short champion bios).
Shurima event is entirely explaining Azir's ascension with a few tiny bits to explain some champions and no substantial lore for most other Shuriman champions. It's a problem that the Shurima event explains Azir more, and explains Xerath, but doesn't actually tell us anything about Shurima or its champions. Also, the whole year and a half of zero lore updates to any of the champions with their lore utterly removed and replaced with a short paragraph grates on people, especially when the whole retcon was so they could make lore for such champions without being extremely constrained in scope and impact.