What is the easiest way to upgrade from davidc502 Lede SNAPSHOT r7210-14cb05909a / LuCI Master (git-18.163.61042-b5a43cf) to the current OpenWrt build without losing settings? I am running the WRT1900ACv2 router.
You will lose your network settings, as the switch config has changed from the old swconfig based ones to DSA based.
Your best bet is to sysupgrade (from your year 2018 build) to 22.03.0 without preserving settings and then manually reconfig.
Alternatively, you could sysupgrade to 19.07.10 with settings, but the already EoL 19.07 is the most recent release to which you can sysupgrade with settings.