I have checked. I did not have access. I have done your Linux commands:
PHP 5.6.40 (cli) (built: Oct 28 2019 18:44:52)
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies
# php -m | grep soap
is empty result.
What to do to install SOAP. I like to to install only on PHP 7.3.