I know it takes about a week, that's not the same though as "Day One".
People boosting you through Nighthold is not the same as alt friendliness, because then by that logic, every expansion is alt friendly.
You're going to struggle to find a group who will bring someone without both their relics when they can easily choose someone who DOES have both their relics, and their artifact actually filled out.
That's not even to mention the point of I'm not sure how you're getting to 880 in one day, that would require nearly all day grinding Mythics/Mythic+ and having really good luck, which is not something your average player can dedicate.
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The Rep boost was implemented pretty quick also.