Existing site on one CMS, need another. Wrong steps lose SEO and content.
Preparation
Backup, URL audit, analytics export, plugin alternatives check.
Content migration
XML/CSV articles, media, users, custom fields.
URL preserving
Keep URL structure ideal. Else — 301 redirects.
SEO
Meta, Schema, sitemap, GSC.
Test and launch
Staging fully. After launch — 2 weeks monitoring.