What was the reason for which you bought BTC?

If the fundamental reason hasn't changed, stay the course.

If the fundamental reason has changed, sell.

When Tether goes down - and it will - more chaos will ensue.  However, if the reason you got into BTC hasn't changed, then stay with it.  That will likely be the bottom.

More than 10 years in.  Nothing's changed except the chasm will have to be crossed.  This is where the wheat will be separated from the chaff.