The new API introduced in v2.6 (#17, #18) seems to be broken due to a change by REWE, it now yields a 404 error:

Traceback (most recent call last):
File "[...]/rewe_discounts.py", line 294, in less_elegant_query
data = scraper.get(url).json()
^^^^^^^^^^^^^^^^^^^^^^^
File "[...]/venv/lib/python3.11/site-packages/requests/models.py", line 975, in json
raise RequestsJSONDecodeError(e.msg, e.doc, e.pos)
requests.exceptions.JSONDecodeError: Extra data: line 1 column 5 (char 4)
FAIL: Unknown error while fetching discounts from https://www.rewe.de/api/all-stationary-offers/[...], maybe a typo or the server rejected the request.

Right now, I have no solution available and the script will not work. If you find the correct API url, please let me know.