Every lock on this list represents a high-security option. There are still a range of options that cover different price points and security but there's nothing that you might consider low security. The vast majority of bikes stolen are not locked at all so start by always locking your bike. Remember, that includes inside your home, your garage, and any type of shed or outbuilding. Kryptonite, Abus, and Hiplok all offer anchor products that give you something secure to lock to so you might consider installing one. From that starting point, the choice is all about security vs usability.
The most common choice is a U-lock. They are very secure, very easy to carry, and there are a lot of choices across a wide range of price points. The challenge with U-locks though is that they aren't flexible in the way they lock. They have a set site and only fit in a specific way. Many e-bikes have larger tubes that incorporate batteries and if you need to lock to something other than a bike lock it can be difficult to make it work. It's even harder because it's more secure the smaller the U-lock is.
If a U-lock isn't going to work for you then you'll want to look at chain options. Chains tend to be more secure for less money. They are also very secure against angle grinders because they are hard to hold still. They are less secure against bolt cutters because individual links often don't match the diameter of a U lock. They tend to be bigger and heavier than a U lock design and carrying them can be more difficult. Where they excel is in their flexibility. If you need to lock your bike to signpost or any kind of non-standard anchor chains can do it for you.
Another common locking solution is a folding lock. Folding locks are less secure than chains or U locks because they've got a lot of pieces that allow for attack vectors. Quality folding locks do their best to protect the hinges but there will always be vulnerability there.  The wide hardened steel makes them difficult to cut with bolt cutters so it's not like they are pushovers and they are convenient. They can be flexible enough for non-standard anchors and they are easier to carry than other options. We included one high-security option here for those that love the form factor.
There are other options available on the market. All kinds of variations on cable locks exist but we do not recommend them for use with an e-bike. They are so fast, and silent, to cut that it's not worth the risk, even briefly for a bike as pricey as an e-bike.