yup, EV training will surely help but i have a greninja with 4 speed IVs and neutral nature, krookodile with 8 IV attack and 9 in defence, again manectric and jolteon also have horrible speed IVs, chandelure, noivern and also lycanroc- all get easily outsped and with their horrible base defences, they get taken down in one hit. My walls have bad defence IVs as well
it looks awesome, also i hope you might restart xenogene someday