Purely Fictional Planet, Critique Encouraged

[CarnivorousJellybean]

NOTE: TK and Azelor provided feedback before I updated this post (and thank you so much for doing so, you two!), there are some points which I hadn't mentioned here when they made their posts. For clarity, I'll put a little * at the beginning of sentences I've edited.

Short Intro
This is sort of a collaboration between me and my boyfriend since we're both huge nerds. It started out as a simple thought experiment: "how would our world have to change for steampunk be a thing?" and quickly evolved into building a whole world with different cultures, global trading systems, and DRAGONS (biology's my main contribution). Basically a place for all our fun daydreaming moments to take place (and possibly for me to hold a D&D campaign in at some point). However nerdy we are though, neither of us are experts in cartography or geology, so help/critique would be appreciated.

Map
I believe these can be clicked for a higher resolution, though I recommend no larger than 33% of the maximum size for the world-map or it starts to look fuzzy and strange from all the manipulations I've done. The spherical maps are done by overlaying the full map into Google Earth and taking screenshots (so no work on my part)
Labelled_World Map of Major Continents.png
Whole world, labelled so hopefully it's more useful
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Aainmhar and Eira
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Northern and Southern poles - *I drew the north pole while looking at maps of Earth for help with how much stretching should be added, so it came out a little similar to Antarctica.
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Unnamed Continent and a really long archipelago - *The southern tip of the unnamed continent was made from islands in the Philipinnes and Indonesia because I found their layout aesthetically pleasing. Is this an okay thing to do or is this as bad as an artist tracing someone else's work?

More Information
I haven't been super fussy about plate tectonics or anything like that - *mostly because I don't understand them. Quite a few of the decisions (like the archipelago in the last picture) were purely artistic. The planet's supposed to be Earth-like, same axial tilt, diameter, and density. The planet hasn't been named, but some of the places have. Basically Brekanburg's like their equivalent of Europe. Aside from that, the little ring of islands called Serpentlyre is probably giving some experts a headache right about now (and I'm sorry for that).

Some of the areas are super blurry and stretched looking at full-res, *this is because I started with very flat images of my continents and had to contort them to look like a Mercator projection. *The ones where it goes straight from black to white are a result of changing the thresholds in photoshop, whereas the slightly blurry edges are from me painting in areas. The style's probably pretty boring (white continents on black), but it makes it easy for me to change the layouts and warp the continents with very little extra work - unlike if I had painted in biomes.

So uh, what do you guys think? Is it too similar to Earth? Any pro tips? Continents too small/large? Anything so unrealistic that it's making you want to rub my face in it until I understand your point of view?