Naked bike with two cylinder is your friend, seating position upright deswai i recommend go topup and get a z250 if you focus on vibration and want second hand bike.
Every cub bike is going to have vibration because they're all single cylinder engines. KTM and Modenas 200s have engineering that sort of cancels out the vibrations at certain rev point but you're still going to feel them, just not as bad as on a typical cub bike (having a full bike frame also helps).
The Modenas Pulsar 200 is heavier because of poorer quality materials used but that does make it more stable on highway, SYM VF3i is not exactly that light either compared to KTM's Duke 200

This is what the actual seating position looks like. As with any bike (including cubs), shifting your weight further back down the seat puts you at a lean angle since you would be sitting on the curve at that point. But otherwise, your position will still be upright. You can also consider a used Modenas V15. Spare parts are still easily found as long as you are within Klang Valley.
If you don't mind buying brand new can consider Keeway 250 or WMOTO V16. Both are heavy, yes. But it doesn't matter that much because they're low height cruisers. GPX Legend 250 also might be good but again, spare parts availability may be an issue. I see KTNS also just released a new slew of rebadged Zongshen cruiser bikes, haven't tried those before so can't comment on them but as with anything from Zongshen, chances are electronics are going to fail pretty quickly. All you need to do is look at the amount of new Modenas Kriss that have faulty signal indicators.
Or just stick to your current SM 110 and wear thicker gloves, install rubber grips.
Maybe go try sitting on some of the bikes first, see whether you like the ergonomics or not.
Thank you so much for the clarification. I had no idea weight distribution and seating position varies from bike to bike. I mean I know but didn't understand v well haha. I also thought cub bikes are best and sporty bikes are for show. Clearly idk what I am talking about. Haha
I still have my demak D7 I go do some make up lah when bujang that time but this bike so vibrate makes me feel like sitting on massage chair..
And the heat...
I like the KTM design and it looks like a comfortable seating position. Ultimately confirm need to sit and test la. Recommended testing how long should I be on the bike lol