Two tips for those of you considering running GNU Emacs on OpenBSD, other than the usual stuff like adding your user to staff.
The first is that generally speaking you want to start large applications in separate processes using for example call-process with nil passed as the argument to the destination parameter, or alternatively to just start applications outside of Emacs, using dmenu or similar. This resolved many of the crashes I was having which seemed to do either with having subprocesses consuming too much memory (running PDF readers, video player, and www browser as subprocesses) for OpenBSD's relatively aggressive process limits, or simply because these subprocesses had some other issue such as a memory leak or they were violating an unveil or pledge rule.
The second is courtesy of the following blog since I couldn't manage to find this out myself: https://omecha.info/blog/org-capture-freezes-emacs.html Apparently there is some sort of issue with OpenBSD freezing when trying to read the SECONDARY clipboard with Latin1 encoding. This clipboard is read by org-capture, and might be used in some other modes as well, along with anything derived from org-capture. No idea why this would fix things but it does:
(setq x-selection-timeout 10)