Found a nice article on Migration from Plesk 18 to ISPConfig 3
Found a nice article on the Migration process. There were some issues during the process but seems easy enough. Thought I'd share this since it's a great panel
Note: The article is in french, my phone translated it via a Google Translate pop-up just fine. No issues here. I recommend you use Google Translate, too when not being fluent in french.
Stumbled upon the article when doing my "monthly" check on ISPConfig Forums. Also learned that there are at least 4 devs replying to inquiries. Always assumed it was mostly till doing a 1-man project. Glad to see it's not like that. All aboard the alternative control panel train woop woop