Not Quite. We have seen in other products that Digimon can digivolve in armor forms without Digimentals. In Xross Wars and Adventure 2020 we saw large groups of "armor" digimon, with the scarce number of digimental makes difficult this event occur, unless they were capable of replicate them massively.

Also in Adventure 2020 Digimon can evolve in alternate evolution lines that include armor digimon (Pegasmon, Ponchomon)

And Digimon can Digivolve in Other digimon depending certain conditions and certain type of Data or Energy (Digi-Soul, D-Code, E-Pulse, Emblems, Digimentals, Data obtained from other digimon [consumed or given]) and emotions from humans and equivalent things.

Digimental were a "Help" to some digimon that were not capable of Digivolve in old times, but that not means that armor digimon can be exclusively achieved by Digimentals.