Beyer Custom One Pro

Audio Technica M50X  Together with E07k or a used E17 

then...

Beats.

ATH-M50X has higher price/performance ratio. 

dt880 premium 600ohm only Rm 999 if not mistaken

If you plan to direct plug in to computer and hand phone, I would say get an easier to drive headphone. M50x + E18 is not bad. (E17 stop production). If you don't mind desktop unit, can also consider Aune T1 mk2 as dac cum amp.
M50x is not consider a bassy headphone actually. The SQ is quite decent at the price range and easily sounds good.

I'm not sure whether you want quantity or quality. Custom one pro though is a portable headphone, it has stronger needs in amp among other portable headphones. Direct plug in, the quantity of bass is actually quite a lot but very loose and blur and not solid. So when you mentioned the bass is not enough on COP, I am not sure whether the quantity is too little or it's not tight and solid.
If you use to Denon, you can go back for Denon. It's one of the headphone company that produce headphone with good bass.
If you are willing to try new headphone, can consider sennheiser hd598 as well. The bass is different from Denon. The bass with better surrounding, more loose and soft, overall is more warm and rich.

DT770 is higher range than M50x if drive well. A lot of musicians use DT770 for music production. It's quite accurate sound but hard to drive. It's won't be easier to drive than dt880 and dt990 actually. You definitely need an amp for it. Direct plug in might be a disaster 
That's only on the condition without a decent amp 

but but u will get the chance to make a fashion statement...   

V-Moda M100

What's your budget? If you go to valuebasket or ebay you can find them cheaper than the retail in Msia