@fde101 Thank you for these precious bits of information. I was not aware integrating visual modifications was a non-standard practice as metadata are already embedded in my RAW files anyway.
I understand the comparison to Photoshop more than Lightroom and never thought of it as an identical copy. I do not want to denature this thread but I always thought Affinity Photo was a Photoshop/Lightroom merge and Designer was a Illustrator/Photoshop merge. That being said, I was ready to ditch the collection and library management features of Lightroom, for a per-file edits inside well classified file structure. Saving my edits through some kind of sidecar file would've been amazing and also crucial for this to happen.
Keeping my edits settings intact AND my RAW file as originals is a must. Not gonna lie, I am a little bit disappointed to learn Photo is not heading in that direction haha; I mean, no way to manage a collection nor to save any of the settings I spent a lot of time adjusting? It's a no go for my workflow. Will have to stick to Affinity Designer and Adobe Lightroom or switch to Luminar for the time being.
Thank you for your suggestions!