Thank you for the information!
So, my game is kind of a mixed bag. A lot of it is rotoscoped and most of it is un-detailed, with visual effects like boiling to add to a surrealist feel mixed with the clutter of a bullet hell. So a pixel art workload really isn't really a problem, and the artstyle kind of relies on being more zoomed out.
I guess now my question is what options do I have with a gameplay window around 700x800. I figure I could add UI elements to expand the overall size of the screen into whatever resolution I end up going with, and trim down the edges of the current play screen as fit, but I kind of can't sacrifice the current way the camera is zoomed out.
Edit: I added a picture example of rotoscoped art for the game (haven't added boiling yet), and an example of manual pixel art for the game. As you can see, pixels are visible, but they aren't really emphasized in game.
If you are making a pixel art game then I would recommend a smaller resolution that will multiply into other more common 16:9 aspect ratios when scaled up - as Frosty said 1920x1080 is the most popular resolution with that aspect ratio.
However making a pixel art game at that resolution increases the amount of work massively, so what is commonly done is to work at a lower "native" resolution and then scale that up in whole integer factors to larger resolutions so that the pixel don't distort.
As an example 640x360 will scale perfectly into 1280x720 (720p), 1920x1080 (1080p), 2160x1440 (1440p) etc etc all the way up to 3840x2160 (4K) and will still look super sharp with zero pixel distortion, as 1px at your native resolution become a 2x2px / 4x4px etc block when scaled up in whole numbers.
There are other resolutions that work too along with the exampel above, there are a couple of threads on here which go into more detail on how to properly scale pixel art games which would be worth you reading, and Pixelated Pope has a few YT videos which go through things too.
If you aren't making a pixel art game then you can usually get away with using interpolation when scaling and it doesn't look too bad.