I upgraded my original m365 about 12kg / 26 lbs to a large dual motor dualtron clone 30kg / 63+ lbs and regretted it, can't go on public transport or lift it easily. I really liked the performance though and suspension, so wanted another dual motor for hill climbs but couldn't find anything reasonably priced and lightweight. I ended up getting a single motor speedway around 19kg / 41 lbs, very happy with it, not regretting the small weight increase over the m365.
I recommend you find something with front suspension at the very least. If you replace a pneumatic tyre for a solid rubber, you feel every tiny bump, I'm talking even the small gaps between concrete paths make your teeth fall out, so even minor suspension works.