The linked GBC version is my fork with some improvements (and more in the works).
The current published release uses a similar compression approach by zeta_two, but in current builds I've switched to the compression by arpruss since total data + decompression code size is now a couple hundred bytes smaller.
Not sure how big the word dict is in your latest version, but you can do much better simply by reordering how you create your index.
With alphabet in order, assembling letters ABCDE: 17345.00 bytes
With alphabet in order, assembling letters EDCBA: 16949.00 bytes
With alphabet order tweaked, assembling letters EDCBA: 16309.00 bytes
Where tweaked means you build your offset as if each position was ordered like this ([::-1] means reverse if you're unfamiliar with Python).
You can also use a prefix rather than variable length encoding, this means you can use 2 bits to represent a number bigger than 2^14, rather than 3. This might hurt your ability to decode though, as you'll have bits that cross byte boundaries.
You can get much smaller using length 3 varints rather than 7 (13,110 bytes), but I presume that would perform worse on GB hardware than staying byte aligned.
Not sure what technique you're using for the answers list, but the compress5.py suggests it's doing a basic bitmap.
Base bitmap is 12972 bits, or 1622 bytes (your file lists 1619, not sure why it's 3 bytes smaller, but all the same). You can "skip encode" (I don't know the formal name for this technique) into 1232 bytes by encoding runs of three [0, 0, 0] as [0], and anything else as [1, X, X, X], saving another 390 bytes.
I tried all combinations of runs between 1 and 7, and 3 is optimal.
Personally, yes. I'm sitting around 50% right now, but have no reservations upgrading if/when I reach the need to. It's something you'll have to play with yourself to see if you can get it working in a way that makes sense for you - I know a few people who felt it didn't provide enough structure for them.
"With respect to your complaint that Cox intercepts and injects our own data in order to display alerts, etc, we note that browser alerts are a method Cox utilizes to bring customers’ attention to important information that may affect their Internet experience."
They'll also appear if you're nearing your data allowance or if their email service (that you probably don't use) is undergoing maintenance. When I last asked, there is no possible way to opt-out or disable these.
Found a GBC implementation as well: https://github.com/bbbbbr/gb-wordle