Backport of CI related PRs on 1.4.x
backports #46543, #46401, #46347, #46260, #46426, #46016, #46370 and #46358

(will change milestones on those, once CI here is successful and merged.)
ooh. looks like the py38_32bit pipeline is fixed by one of these PRs too. thanks @simonjayhawkins 