The site you linked to shows Dell part 2D76T which is the same as 3KWGY. The 3KWGY Liteon 240W AC power adapter was used on both the 2019 m15 R2 and the 2015 15 R2.
I need to renew mine because the cable is broken and half the time I'm trying to lay it so that it charges. But there are two on the website, one is for the 15 R2, I suppose the m15 R2 comes under that? Is this the one I need? The other one doesn't state for which laptops. And not sure why it's a few euro's cheaper. 
m15 R2, adapter