I understand the high level goal, but there's not enough information here for someone without an openbsd system to understand the actual issue.
To compound things, the use of openssl in wezterm is across multiple ssh library implementations as well as directly in wezterm itself, which increases the effort to resolve things.

I have no plans to sit down and make this happen for openbsd, but am open to reviewing PR(s) that help to reach this goal.

One thing I can suggest is to add conditionals that only activate when libressl is detected.
I made a patch for kitty that should give you the gist: kovidgoyal/kitty#7904

You might also find this helpful:
https://github.com/openbsd/ports/tree/master/lang/rust/patches