Upgrade was smooth as is to be expected with Fedora and everything is running smooth. Libadwaita is not as bad as I thought it to be, and it actually looks really good. I wish they had taken the time and effort to create a GTK3 theme for applications that are not libadwaita aware, but fortunately someone else did. It does look horribly inconsistent without. Bad move.
Other than this, I do not miss the theming at the moment now that I added some transparency in the top bar and dock.
After building and setting up my new computer and subsequent move away from the Apple Mac ecosystem, I was left with an issue that the site I had built was setup using a Mac-only tool and could not be migrated to Windows. After mucking around with different tools on Windows and hacking things together, I have now decided to go platform independent and recreate my website using the ever popular WordPress CMS.
Setting it up on the Synology was a breeze and after finding a suitable theme for my needs I have now started to get things up and running again, adding the content, etc. So far, it looks pretty ok and this may indeed be the way to go.