This issue has been raised in France but it turns out most couriers are "micro-entrepreneurs" and appear to be quite content with both the social benefits and the flexibility (as reported by Deliveroo and as independently assessed by the Sénat in 2020).
Anecdata, I had a couple of chats with some couriers and it seems to correlate with the Sénat finding. TBH I expected it to be otherwise.
https://fr.wikipedia.org/wiki/Deliveroo#Rémunération_et_stat...