I'm almost tempted to say "Don't Search on Atlantic". But, you won't find them anywhere else, and that's the actual root of your issue.
I'm pretty sure, from doing searches on all shards when looking to complete certain collections, that Atlantic is the only shard that has that "too vague" issue, as the database software they set up for Vendor Search can't handle the vendor volume there. Since 99% of the stuff being sold on vendors is on Atlantic, and there's too many people going around cross-sharding events that decide to loot local vendors to take stuff back to Atlantic for resale (I was one of several that used to sell resources on my home shard, until we realized that all of our vendors were being emptied within 6 hours +/- of event time, and some of our crafted items from the same vendor with name tags showed up for sale on Atlantic the next day). It's been almost a decade since the last time I was able to find a PS for sale using vendors on any shard (that allows transfers) other than Atlantic