Given the rise and rise in popularity of EV's you would wouldn't expect rampant depreciation, but it will be interesting to see what happens with these luxury mid sized SUV's (Jaguar I Pace & Audi e-Tron) from the main players.
High demand for used EVs may well keep their price close to that of their new counterparts, however it seems likely that new ones are going to decrease in price during the next five years. There is also the impact of any upcoming government subsidies.
I personally see a lot of depreciation risk around EVs and wouldn't buy one until there is a bit more certainty around how the pricing is going to trend over the next few years.
There would be less deprecation risk in buying a brand new EV, compared to some types of ICE cars. As the lower running costs offset a lot of the deprecation risk.
As an example, compare ICE Utes to sedans. At almost any age bracket, the Ute will be worth more than a sedan with a similar distance travelled, overall condition etc.
My advice to anyone who is considering buying A new or near new ICE vehicle- Buy a diesel Ute, Van, or SUV. Or if you have to get a hatchback- Buy a hybrid. As such vehicles will be needed by people who tow caravans, boats etc long distance. And it will be ages before an EV becomes available which can do that. Let alone one that costs less than $100K. Hybrid- people who do lots of long distance driving, taxi / uber drivers etc. If you don't want a diesel or hybrid, get a high performance petrol turbo car. As you will always have the boy racer market to sell into.
A new or near new ICE sedan, hatchback etc would be about the worst choice. As buyers of them in the secondhand market are very price sensitive. And that market has large subgroups, those who will happily pay heaps more upfront as long as running cost savings justify the high purchase price. And those who are on very low incomes, where paying more is simply not an option.
EV hatchbacks, sedans are already available both new and secondhand. With lots more models planned and available soon. Ice vehicles in that segment will be hardest hit by depreciation.