For quality, Traditional Chinese, Thai and Indonesian cards as usual were printed in the same factory as Japanese, so they have the same quality as Japanese SRs/SARs (with unfortunately some minor flaws you would expect from SV-era cards such as slight texture shifts). Korean was also printed in their own factory as usual so texture and/or quality will be close to TPCi prints.
For rarity, all languages were released as top prize cards in local events, so no need to expect they have huge differences such as “extremely limited events” vs “regular events” vs “mass production (sets/gift boxes)” like we’d seen in Charizard VMAX distributions. Rarity of each language will be purely based on number of events held in each region, so you’ll get a sense of it if you’re able to estimate that.
If the number of events held stays roughly the same from previous Sealed Battle events, you should expect the Traditional Chinese copies to be the most distributed. However as Traditional Chinese:
- Was the first language the cards were announced in and distributed which triggered FOMO purchases, especially as the cards were never released in Japan and TPCi regions and thus attracted collectors from those regions as well
- Had demand from Chinese markets which is significantly larger than other languages (with Mainland China counted in as the cards were yet to be announced in Simplified Chinese)
Those had resulted in a noticeable premium added to the Traditional Chinese cards regardless of their actual rarities against other languages. If you don’t have specific language preferences, you can just grab the cheaper language you found on the market.