The Nissan Leaf has done the EV movement a bit of a disservice with the battery degradation the earlier (2010/2011) models suffered, especially when used in hot climates. They've slowly improved things, to the point that my 5 year old Leaf still has 90% of its battery capacity - the Irish climate is perfect for them. But this is just the Leaf, you don't see this level of degradation with the other models out there - ultimately the ones with decent batteries (Samsung/LG/Tesla) that are actively cooled. Plenty of data out there to back this up, for example this survey showing an average of 90% capacity in Teslas after 200,000km https://www.engadget.com/2018/04/16/tesla-battery-packs-live-longer/. In-short, for your average driver this degradation is insignificant and unnoticeable.The battery will wear out. Warranties are around 100,000Km or 8 to 10 years and the replacement cost is €5000+.
EVs certainly suffered from significant depreciation in the past, because there was some fear around them (causing lack of demand) and they were expensive to buy. But since the diesel debacle and the push for move EVs on the road, the newer models are holding up as well if not better than petrol/diesel cars, and older models have actually seen an increase in their secondhand value (paid €10k for mine, worth €12 a year later).
I really could not recommend people go out and test drive an EV, chat to others who own them and get honest hands-on feedback, there's a lot of inaccurate information knocking around, most of it in the 'old wive's tale' category.
To be clear though, if you drive a huge amount then EV is not for you yet. If you own an apartment so cannot get a home charger or do not have a work charger, an EV is not for you yet. If you want to save money by moving to EV you will need to look at an older model, new EVs are still expensive enough (great spec'd cars, but if you're in penny pinching mode then things like self driving are probably not required ).