Как найти ключ по значению?
Перебором.
Всем спасибо, Сергей Горностаев, MinTnt, MinTnt! Натолкнули на мысль!
Собсно Json
#!/usr/bin/env python3.9

import json
import re
from collections import Counter

with open('/home/delvin/codding/pogoda/sensorsNearby.json') as json_facta:
    fact = json.load(json_facta)
    json_facta.close()
array = fact['devices']
numkeys = Counter(i for val in array for i in val)['id']
startnum = 0
sensor = 0
unit = ''
pressure = 0

while startnum <= numkeys:
    for device in fact['devices']:
        if device['location'] == "Ленинск-Кузнецкий, Городская ул., 10":
            pressure = device['id']
            temperature = device['sensors'][-1]['value']
            temperature = round(temperature)
            unit = device['sensors'][-1]['unit']
    startnum += 1

print (f"{temperature}{unit}")
Выхлоп:
27°