Pro-Ject Debut Carbon DC with Ortofon 2M Red Cartridge: BASS sounds 'muddy' The Reason?

Chakster means well and he's right. But you do not need to go nuts spending at this point.
Assuming you sent the Pro-Ject back, and the support you are using isn't a tea chest or an ironing board, consider getting the Technics GR and a cheaper cartridge like the Nagaoka MP110. 
Get the Schiit Mani from Amazon. Connect it to the aux input on the Denon.
Ensure all is in order with set up. Read up on VTA, SRA, etc. Don't be afraid to adjust and listen and adjust. All set in an hour.

Now, your Denon is probaby not great, and in due course can be updated. The 630 speakers are big and may be overloading your space if playing too loudly. And we are back to acoustic feedback. Set tone controls flat and loudness off. See how you get on. Then and only then, can you move forward. 

I answered your question about what table you should buy on the other thread.

@klimt This is going sideways. Back up. You are all over the place. That's okay. 
Your original problem was muddy sound. You didn't apparently address suggestions about acoustic feedback. You assumed you needed a better cartridge. That won't necessarily fix things. Then, in another thread, you said you got rid of the table. Now you want to get a phono with moving coil settings while you've not landed yet.

You are answering your own question. Get the better table.
BTW, bass varies by record. Just because some sound better than others doesn't mean the fault is not in the table/setup.

OP sent the table back from whence it came.

Don't worry about the cartridge for the moment. What’s the table standing on? Try standing it on a sheet of granite, paving slab or thick glass. Is there a dust cover on it? Remove it. Is it in the firing line of the speakers? Stuck in a corner? Acoustic feedback can give muddy bass.
The Denon amp is old and most likely has a crap phono stage. Buy a Schiit Mani from Amazon and plug into an aux input.