Hardware and performance

So you moved from
$CFG->tempdir = '/mnt/moodledata/tempdir';
$CFG->cachedir = '/mnt/moodledata/cachedir';
external volumes (mounted through the network?) to
$CFG->tempdir = '/var/moodledata/tempdir';
$CFG->cachedir = '/var/moodledata/cachedir';
which are local drives - or the equivalent in Azure and that improved performance?

Not surprising. You can convince yourself by running Moodle benchmark https://moodle.org/plugins/report_benchmark.