The arrangement I ended up with, offered because it removes the anxiety rather than answering the question: two tiers on purpose.
A daily tea, bought in quantity, chosen because it is good enough and forgiving — it survives being brewed carelessly while I work, and I do not think about it. And a small amount of something better for when I am actually paying attention.
Why this works better than finding one right price: the value of an expensive tea is almost entirely in the attention you bring to it, and most cups do not get that attention. Drinking a very good tea at a desk during a meeting is spending money on something you are not receiving.
On the freshness angle, which matters more than people expect at your consumption: buying 100g of something excellent that you drink over eight months means most of it is not what you paid for. A cheaper tea drunk fresh often beats a better tea drunk stale, particularly for greens and lighter oolongs. Buying smaller amounts more often is a genuine quality improvement that costs nothing.
And on the descriptions: ignore them and buy from sellers who tell you the concrete things — where, when picked, how processed, what year. A seller who gives you facts is telling you they have them. One who gives you only misty mountains usually has only misty mountains.