Quick answer

Validate JSON files, find missing commas, broken quotes, invalid characters, and bad copied content from Android editors.

JSON Errors is a focused guide for the exact situation described below.

For JSON Errors, focus on files, paths, storage and backups and use the output to decide the next small fix instead of reinstalling everything.

What to check

For JSON Errors, read the first line that names a missing file, package, port, module, or permission.
For JSON Errors, keywords that usually matter are: JSON, Errors.
If the first command for JSON Errors gives a different error, follow the new clue instead of forcing this guide.

For JSON Errors, replace placeholders only when they appear in the command.

python -m json.tool data.json > /tmp/checked.json
python - <<'PY'
import json
json.load(open("data.json", encoding="utf-8"))
print("JSON OK")
PY

python -m json.tool data.json > /tmp/checked.json — runs the script directly so the first traceback can be read for JSON Errors.
python - <<'PY' — runs the script directly so the first traceback can be read for JSON Errors.
import json — checks the part of the files, paths, storage and backups workflow that usually causes this issue for JSON Errors.
json.load(open("data.json", encoding="utf-8")) — checks the part of the files, paths, storage and backups workflow that usually causes this issue for JSON Errors.
print("JSON OK") — checks the part of the files, paths, storage and backups workflow that usually causes this issue for JSON Errors.
PY — checks the part of the files, paths, storage and backups workflow that usually causes this issue for JSON Errors.

Save the JSON Errors output before editing files.
Change one thing at a time while testing JSON Errors.
If the JSON Errors error changes, read the new clue instead of repeating the old fix.

Running the JSON Errors command from the home folder when the project is somewhere else.
Following a desktop Linux answer that ignores Android storage paths while fixing JSON Errors.
Closing Termux before copying the output that explains JSON Errors.

If json errors the file path still does not make sense, send a screenshot of pwd, ls, and the error through the Store.