Is it easier to get into a PM role or a PMM role?

Both roles are quite tough to get into without experience, but PM is marginally easier.

1. Companies will typically have more PMs than PMMs. The PMM to PM ratio is roughly 1:4. Even if the company prioritizes PMM roles, it's rare that the ratio will get higher than 1:2.
2. There are fewer PMM roles in the industry. Just doing a quick search on LinkedIn shows that there are about ~100k open PMM roles, while there are about ~280k open PM roles. 
3. PMs typically get hired first. Most companies will start with PMs. This is unsurprising since the goal at early stage companies is to build the product and get to product-market fit. A PMM role, while important, is usually secondary.
4. (counterpoint) PMM has a wider pool to draw from. Most marketing, sales, and biz dev roles, can transition into entry-level PMM roles. In contrast, there are fewer paths into being a product manager (common ones are business analyst and engineering). 

Finally, it's worth highlighting that, in general, both roles are hard to get into. There are very few entry-level PM or PMM roles. If you only have an undergraduate degree you are unlikely to land a PM or PMM spot. I've had many colleagues who've had extensive careers, done an MBA and then transitioned into a PMM role. Similarly, many PMs come with long software engineering backgrounds. 

If you are a new graduate and looking for a PMM or PM role, I would recommend looking for PM internsips and transitioning this into a full-time position (PMM internships exist but are less common for the factors mentioned above). The alternative is to go into one of the other careers mentioned above (marketing, sales, biz dev before going into PMM or software engineering before becoming a PM). 

It depends on what your background is. If you have a background in traditional marketing, it's going to be easier to get into product marketing by learning both the domain and the product in-depth. The advantage of coming from marketing is that you already know what a demand generation organization needs from product marketing in order to effectively articulate the product and fill the funnel.

It's easier to get into product management if you come from a technical background such as engineering or design, but also including roles like technical support, customer success architect, or professional services consultant. You'll need to pick up the basics of how to develop and articulate strategy as well as shifting to more long-term thinking.