Heirloom

Not sure if this helps, but if you'd like a comparison, my account is near level 1000 right now (near the second reset) and I've been playing close to 4 years and grind every battle pass, and I just got my very first heirloom a week ago.  I have no idea whether this was luck or the gacha pity (500 packs).  I never purchase packs except the ones that come with the battle pass (I get the paid level every season) so maybe that's why it took me so long.