Lvl 30 4* troops bring 70 points each.
(How to calculate team power, including troops!)
Highest 3* is costumed Hawkmoon with 468, unemblemed.
(Costumed Hero Card Values Release 1 - Original, Unequipped, Equipped - #11 by Razor)
Emblems put 5 TP each, that’s 100 for node 20.
(Emblem/Talent Grid power addition to hero card power? - #3 by Rigs)
5 Hawkmoons, with maxed costume and fully emblemed would bring 568 TP + 70 for the troop = 638 * 5 = 3190.
That would be the max possible TP for 3* heroes, what’s still far below 3,5 k.
I hope, this is correct…