I'm going to share my experience with "chain testing" on my 1500W BBSHD bike.
I used the park Tool CC-2 Chain Checker.
https://www.parktool.com/product/chain-checker-cc-2
I use this because it puts a number on the amount of chain stretch. This can reflect not only the state of wear but the strength and precision of a new chain. A No=Go type gauge just tells you when the chain is worn out. I look at what stretch a chain breaks in at and how long it holds that figure. I can also decide to rotate that chain onto an unpowered bike while it's still in spec. This will prevent wear to the special chainrings many of us run on our E bikes. A worn chain has a longer pitch than a new one, and directs all the force onto one link until the cog wears to match the increased pitch. You end up replacing everything if this goes on too long.
My climate is often damp and windy, sandy environment, and hard acceleration and high speed operation (+30mph)are normal. No long climbs though. On the advice of a couple local bike shops I use wax based lubricants. Both melted wax soaking and external apllication. I tried installing chains with just the factory lube which is supposed to be the best, but found that in my environment they rust. This is cosmetic but I now drip wax the chain before installation.
I tried the KMC Z chain. I found the removable link to be too fragile. It bent over and became tight on the chain and hard to remove. It also stretched fairly quickly. To be fair the BBSHD was causing a learn as you go situation regarding driveline maintenenace and would have lasted longer if I had taken better care of it. Also my bike runs a flat 50T ring and 8 speed casette. It's badly cross chained in the 2 lowest gears. They get used without power for sidewalk use around pedestrians. This is probably why the link folded. I next tried the Wippermann 8SE E bike chain to see what it was all about. I had used their 8SX stainless steel chain on my XC bike and liked it.
It broke in at .2mm stretch and stayed there a while. Then gradually went out to .25, and when removed after 6 months it was at.5mm, which according to the Park Tool chart is a new chain.
The Wippermann Connex link worked and didn't stretch or deform. They say not to reuse, but with my obsessive lubing program that could get expensive so I got into the habit of reusing it then forgot about replacemnet completely. Eventually it "removed itself from service" on it's own. Fortunately my front roller chain guide kept it on the chainring and it fell harmlessly on the concrete bike path I was on. A spare link would have got me going again. But I had a nice long walk to where I could ne picked up. At least it wasn't one of my midnight rides. I did have a spare chain already. When I installed it there was a problem with the chain skipping in the top 3 cogs. It was traced doen to a defective Connex Link. Enough of the 2 piece links for me. That chain could have gone into the spokes of my rear wheel at speed in traffic. On the advice of my LBS mechanic I had purchased a Rohloff Revolver 2 chain splicing tool.
https://www.rohloff.de/fileadmin/_migrated/content_uploads/Beschreibung_Revolver2.en.pdf
These are not cheap, but neither are Wipperman Connex links when replaced often. I ended up having my LBS rivet the chain on. Not much choice really I was out of Connex links. But for my application and riding environment I think it's the reasonable choice.
I found the Wippermann 8SE to be up to the challenge.
The Connex link is a strong part but not as durable as the chain. If replaced often, and carry a spare, it's a useful part.
The Rohloff Revolver 2 is the solution for me. They're up to version 3 which can do 11-12 speed chains. Parts are available so a used one, or ask for a discount on the older version is possible, since it's slightly obsolete for modern bike shop use. This tool securely positions, and supports the chain, cross peens the pin to secure it, and this also marks the pin where you reconnected the chain so you won't use that link again for repair. I rotated the used chain to my XC bike and had some chain left over to practice on. It's actually quick and easy to use. If it's too expensive for you it may be almost as cheap to have a bike shop R&R your chain for you as buy the Connex links.