The loss does not affect the SE tax; only taxable income and the QBI deduction are affected. the loss should flow to form 4797 (not schedule C). that loss does not flow to schedules C or SE.
from schedule SE instructions page 4
Income and Losses Not Included in Net Earnings From Self-Employment
8. Gain or loss from:
a. The sale or exchange of a capital asset;
b. The sale, exchange, involuntary conversion, or other disposition
of property unless the property is stock in trade or other property that
would be includible in inventory, or held primarily for sale to customers in
the ordinary course of the business; or
