Rack and fenders are easily removed, although some prefer to ride in groups with fenders, especially if they live in a wetter climate zone. On the Tesoro, rear fender stays would have to be fitted if the rack was removed but the fenders remained. As to the front suspension fork, I assumed, as an older rider, the greater comfort afforded by a suspension fork will enable the rider to sustain longer rides, paying less of a price in pain and discomfort after the ride.
As a class 1 (sub 20mph) with flat bars, and a more upright riding position for less than $5,000 this bike ticks most of the boxes for the OP and weighs the same as the Turbo Vado 4 in which he expressed an interest. If one wants to shed much more weight, then carbon fiber is the best way to do that but the price will be driven well beyond the OP's budget. The Trek Allant series might have a model that works but they are pricier and weigh even more.