Unless root is an absolute must, I'm not aware of anything that will force a wipe. If a patched kernel fails to boot, you can just flash the unpatched image.Note that I followed the instructions in the OP exactly, including latest SDK and the linked version of Magisk. The issue may have been that I was coming from an old release (Jan, I think). As upgrades are always high risk, I saw no point in risking a wipe until Dirty Pipes was patched.
I have backups of all my important stuff, it would just be nice to be able to say "just restore it all". I'll take a look into Swift once I get everything back the way I want it, thankx