The device itself won't charge any faster, and hence not get any hotter, than what it is originally capable of. For instance, if I plug my phone that can go at 15W into a 100W charger it is still only going to get 15W of power at most. USB power delivery is standard across the board so in theory it should all be mix & match. If you have problems with charging your Lenovo via USB-C I would consult a Lenovo site as you're not going to get any help here other than "it should work".
Users have reported that they cannot charge the device using usb-c adapters and there are talks that usb-c charging is disabled for the 15" version by Lenovo. I don’t know if this makes sense. Is it just like the iPad Pro, the higher the Watt, the faster the charging at the cost of some heat? Is there a potential of hazard for charging via usb-c on a laptop that is not MBP 16"?
I think you should charge the Lenovo with the charger it came with it and be done with problems. USB C to USB C charging is and remains problematic between varying manufacturers. Reputable battery's and chargers will only charge at their given rate and will only charge faster if safe to do so.
Powerful notebooks require a lot of power, if an issue purchase additional chargers. I don't know what the Lenovo pulls, however my Asus has a 230W charger and I wouldn't consider charging it via USB C as the charger will be maxed out all to often, temperatures will soar.
If Lenovo has disabled charging via USB C then it's no longer USB C, as that's the point of a standard.
Q-6
That would be the sensible person's approach.So the best action is to forget about it and use the charger that came with it?