Sounds like a few choices, to be fair, when i used the ebike for commutes over a few days it saved the fatigue, so able to do more journeys, it’s just that 15.5mph limit and my mindset, like most, you have a cadence you stick too, and you want to go at a speed you’re comfortable with, and on flat or slight downs, it’s over that.
But, with the options you’re on about, the ebike looks like the most logical, honestly the thought of going back on the trains terrifies me, that first commuter train of the day, filled with the same folk, who have their same seats, who take up the bike bit with their crap every day, the delays, cancellations, cost and so on, i’d choose a slow ebike pootle every day, i’d rather change my riding style than get back on the commuting trains these days!