No, Dyne has repeatedly confirmed on Twitter and Patreon that Spencer’s route is a canon route. In Dyne's words, Spencer has loved Eric since before the start, and he has to watch him go through each other route and find love with someone else. Also according to Dyne, Spencer's the only person that really ends up missing out if you don't choose him. I have no links, but it's true and many people have already seen this. If you don't wanna to believe, that's fine. But he's Eric's canon lover, clear and simple. And if some route is recognized to be a canon by developer, then this doesn't mean that all other routes aren't important. This is not true, all routes and characters are loved and important:)
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he literally said in the interview he didn't want to say who the canon lover was because then people would get the wrong idea about the direction he wanted it to go in. You can literally go to the interview and watch it and see it yourself. Spencer is Dyne's personal canon but he specifically doesn't set one as the definitive because, as he said himself, he wanted to leave that up to the player.
As i was saying, i saw other comments about Spencer's route being canon (Twitter and Patreon) and he confirmed that the route is not just his personal canon but simply the canon, true route of the whole novel. So I will stick to my statement. You can also ask Dyne about it in details on Twitter. But if you're right, it's okay. Spencer will always be my canon (as well as canon of many, many people) no matter what ^^