So many newbies think the DIY/conversion makes a decent e-bike. This (kind of) reminds me of the origin of the word "a car", derived from those horse drawn carriages equipped with an internal combustion engine. After a while, the automotive industry started designing "motor cars" that were a motor car from the first moment. Here, let me end drawing a parallel before some notable members of this Forum become really upset
@jplanaux: As you have described it, you ride asphalt for exercise, and your rides are pretty long. Your current ride is a Trek Dual Sport. You are probably an able cyclist, and you need a lightweight, reliable e-bike that could be ridden without assistance, and the assistance would only be used against the headwind or for climbing hills.
My advice is you book a demo ride for a Specialized Turbo Vado
SL. I am 60, plagued with three major ailments. One of these ailments means bad legs (that cannot be improved). Vado SL has become my everyday ride. Just look at my avatar
To complete the description, I really love very long rides, with a Metric Century being my favourite distance, and with a single Imperial Century made so far.
No hassle, beautiful most modern lightweight e-bike with low power motor and lightweight battery, covered by an excellent warranty, and even not
that expensive.