I recently made a second account, just to screw around, and so far, the second account seems way luckier than my main one.
I made my main account at beginning of the summer event, and I've used every ticket and almost every quartz that I've gained since then, and I have summoned 0 SSR servants, 1 SSR CE (Pirates Party), and 3 non-tutorial SR servants (Kiyo Lancer, Anne Bonny Archer, and Anne Bonny Rider), and my tutorial servant was Elizabeth.
I made the second account like the day before the Prisma event started. Even the tutorial roll was luckier, since I got Heracles. Then since it was the last day of the summer banner, I went ahead and did a 10-roll on it with my Fuyuki quartz, and got Martha Ruler as well a Limited/Zero Over CE to toss on Herc. I've used whatever handful of summon tickets I've gotten so far on the Illya banner (maybe 10 tickets or so?) and so far I've gotten Astolfo, another Limited/Zero Over, Illya, and Medb. So out of maybe 10 summons I got a nice SSR CE, two SSR servants, and a SR servant. And just now, as I was writing this, I decided that my sample size was too small, so I just reached over and did a 10-roll on the story banner and got a Mordred as well.
Neither account is particularly old, so my sample size of summons on both of them is pretty small, but so far the difference in luck seems pretty uncanny. Has anyone else who plays multiple accounts noticed something similar? I know that this is a far fetched theory, but maybe DW's random number generator gets seeded by something that is specific to the accounts or something.