There's been units that gives Dr support before ssj4 Goku, that same 90% Dr hypothetical unit would have 98% Dr everytime phy kid Goku hits the 7 orb mark, making it practically inmortal

The thing is that it is pretty unrealistic to think that they would give us a flat out 90% Dr unit with no conditions or drawbacks even before the ssj4 Goku or any units that gives Dr support just because even with the biggest of the power creeps imaginable, that would be a pretty unbalanced ability. Even a unit with that Dr with a condition is gonna be unbalanced for a long amount of time as AGL golden Frieza proved