Alright, after much searching etc.. I think I've found the ideal LCD replacements if anyone is interested..
The original screen is an LG LP141XA (DIAP). I assume the D1AP is an Apple specific part. Anyways, grabbing the datasheet here:
https://datasheetspdf.com/parts/LP141XA-D1AP.pdf?id=723307 we can see that the LCD has a typical brightness of 115cd/m2. On page 17 we can see the measurements of where the (20 pin) connector is too.
I've found two slightly newer LG models, which were somewhat easy to find on fleabay. LG LP141XA (A1), and a LG LP141XB-C1. You can grab the datasheets at the same site as linked above, but to save you the time. They have the exact same dimensions for the connector, same pinout, etc.. and they're 170cd/m2 (so ~30% brighter than the stock panel).
I also found this huge list of "compatible" LCDs @
https://www.laptop-power.co.uk/laptop-screens/apple/powerbook/series-g3/model-pismo-m7572.html However, after pulling datasheets (if I was even able to find them) most of the NON-standard brands were either impossible to find, or really expensive. For the name-brands, the Sharps I couldn't find proper datasheets for, but by eyeballing them on eBay, it seems like the inverter connection is different, some are 30 pin too. The Samsungs had decent specs, but are also 30 pin. The last 10 pins aren't used as per the datasheet.. but the other 20pins are arranged differently than the LG, so you'd have to re-order then or build some sort of adapter. They seem to be around 150cd/m2. So not any brighter really than some of the available LGs.
Now, some suggested that for the price, I could pick up a used Pismo. Sure, but the screen is going to be just as old and in (probably) worse condition than what I'm using now. So I'd prefer a new panel (if I can find NOS). All in, I found one of the brighter LGs for $65 CDN.
Hope this helps someone else!