Learning from research papers in a developing field
Seems like a developing field is a discussion that a community of researchers engages in.  To participate, you'd need to:

Speak the language, e.g. know about quantum computing terminology.

Know the background, e.g. quantum physics and computational theory.


Once you have some basis for understanding the discussion, then you focus on getting your own ideas straight.  In the end, it's really all about you; sharing research results really isn't a goal so much as a duty to be performed when/if you become the foremost authority on some particular understanding.
If you're a younger student, you've probably got a lot to learn and develop before you can really enter that arena.  But, if you're interested in it anyway, it seems like you could do two things:

Focus on the well-agreed-upon concepts.  You don't need to understand them or even be able to use them just yet, but have them in the back of your mind as you progress in your more foundational studies.

Take note of the skills and tools that seem to be most useful in the current community.  For example, if the field seems to be best-attacked through a particular branch of mathematics or using particular computational tools, then you might want to put acquiring those skills on your to-do list.


Getting to Philosophy

Papers often lead me down rabbit holes as well - tracing citations (I could tell a few entertaining stories about that alone), looking up terms (&quot;oh, that's what you meant...well, why didn't you say that?&quot;), and going down that oh-so-fun Wikipedia trail. You know, look up word, read third word on page, click on that, then continue until somehow you end up at philosophy (ironically, the previous page doesn't end up at philosophy, if I did it correctly).

Definitely, Philosophy is exactly where you want to end up!  Anyone who can't trace their field back to Philosophy hasn't understood it so much as memorized it.
If you know exactly how to get from basic philosophical principles to the current state-of-the-art, then you can really claim to understand the field.
Questions

What tips do you have to get the most bang for your buck reading a paper and retaining that understanding?

Lots of profiling.  For all anyone knows, that random gibberish full of typos and conspiracy theories on Reddit is the deepest, most correct theory of physics ever.  But, since it's probably not and there's only so much time in the day, your bets are better hedged by focusing on content that appears to be of higher quality.
To that end, you should develop a bunch of prejudices over what's likely to be better content, then selectively focus on it.  Sure, if you're truly out of stuff to read, then maybe you'll end up going through that weird Reddit post; or, if you've got too much good stuff to read, you might not even be able to make time for Einstein's words.  It's all relative.
Examples of common prejudices:

Prefer scholarly sources for widely understood concepts.

Prefer blogs and communications from top-experts for the-very-latest commentary.

Well-formatted over poorly-formatted.

Thoughtful over thoughtless.

Analytically precise over vague.



How do you help restrain the rabbit hole?


Follow the rabbit hole down as far as you can go without losing sight of the light of day.

Understand where you've ended up, and build a solid foundation there.

Build back up 'til you're out of the rabbit hole, standing on more solid ground.

Rinse and repeat, iteratively falling down further and building back up more.  The more you do this, the greater your understanding grows.



How do you know when a paper's trustworthy?

They never are.  Whenever you read a textbook - even the best-known ones in well-developed fields, e.g. introductory Calculus - never just trust it.  Put each word on trial, and absorb only the ones that you can't tear down.
You often need to memorize large amounts of content without first thoroughly scrutinizing it.  All of this content should carry a red flag in your head that labels it as unscrutinized claims.  If there should come a time where you really need that information, or want to build upon it, you should really scrutinize it first.