In my experience asian pears are as hardy as European pears but not hardier. Hybrids of both and other pears such as hybrids of siberian are hardier than all the others. When new genetics are introduced some wonderful things come out of the mix. Southern pears like kieffer, ayers, hood etc. are hybrids. They are far more resistant to fireblight. There is signifigant effort being put into testing in that area https://extension.psu.edu/a-new-fire-blight-resistant-pear-bell
https://www.ars.usda.gov/ARSUserFiles/20721500/catalogs/pyrcult.html
Pyrus bretschneideri an interspecific hybrid of Pyrus pyrifolia x Pyrus ussuriensis
Normally when i see blackened tips of a tree it is one of several things eg. weather issue excess wind, sun or water, bacterial damage such as fireblight, fungal damage, or insect damage. If you sprayed for fungus and insects we can eliminate those 2. Fireblight would progress or not in 17 days. That leaves weather related issues. Considered other possibilities that were brought up, which is an insect resistant to your management. That is possible but unlikely if you have a good management system. Last year i received fireblight strikes on my harrow delight and harrow sweet has got them before as well. They are specifically bread to handle fireblight. Last year i was interested in the disease progress on the tree. The disease made it 8" on the tree and stopped. First sign of infection looks similar to your issue but progressed rapidly. Harrow sweet as sn example is highly resistant to psylla. Do you have a current picture?
25 Harrow pear varieties
What was the fresh cut im seeing in the photo? My guess is the ambrosia fell into one of the possibilities i brought up. Most of my orchard is highly disease resistant. I discussed thoroughly what penn state pear research had resulted Bell Pear aka US84909-391 . I would highly recommend looking at these varieties in the highly fireblight resistant type.