Yeah. It's 5.5e. It's a new edition.
There have been significant enough changes to the main structural elements of the game, namely classes and heritages but also spells and feats, that I consider it a new edition.
It's not as drastic as the 3e/4e or 4e/5e jumps, but very little -can- be. The change to 4e was SO dramatic in every structural element as to essentially become a new game even if they maintained the "d20 System" basis.
But compare 5.5e to 1e and 2e AD&D and more importantly to the 2e and 2e Revised rules in TSR 2159.
This is how Steve Winter described the Revised 2e changes. Small and subtle changes that you'd need a tremendous memory and to read the books very carefully to find.
5.5e's changes are not small, or subtle. They are writ large and explicitly advertised on Youtube channels discussed by the designers to explain why they're there. Not just minor or even moderate changes to specific class features, either. Entirely -new- features have been added to classes, like the Cunning Strike of the 5.5e Rogue.
If you can do an 8 minute long video about the changes you've made and the "New Twists" to a -single- class, that's a new edition.