In normal times it takes up to 16 weeks or more to process an Amended 1040X return. But these are not normal times.
They closed in March and still have limited staff. They just started opening the mail in June that's been stacking up. So you have to keep waiting.
See this IRS page for the latest information
Then once they start opening the mail, After 3 weeks you can track it here,
Sorry ... but due to the Covid shut down that lasted almost 4 months NO mailed in returns were processed in fact the envelopes were not even opened. The IRS just started opening mail a month ago and they have more than 10 million to open and process ... so the normal 16 week processing time for amended returns will be more like 6 to 8 months. Calling them will get you nowhere ... once your return is finally in the system you will get the progress report on the IRS web site ... check it once a week until it appears :