I won’t say easier cause it’s not hard, it’s just going to take ridiculously long, especially if you don’t grind out many PvE maps with her.
To unlock Galilea only requires 800 minion kills and it can be with any battleborn/weapon/ability and even then you often unlock Galilea based on command rank just because it takes awhile to stack up that many kills.
But this one lore part of Reyna requires 1000 kills and with a low damage weapon without aoe. I’ve gotten Reyna to 10/15 rank and only have it at 265 kills. Most of my playtime with her ‘is’ in vs but I get decent minion scores every game and have played her in a few PvE games. Just you need that last hit with that bad weapon and as your trying to do that often someone else comes along and smacks enemies with something stronger.
Feels like it should be around 400 if it’s expected to be done by 15/15 Reyna and as low as 200-250 if you should be getting it around the 10/15 rank spot.