This is from google AI:
"Not a universal loophole:
While Woolwich successfully used this with Saliba, a similar attempt by Tottenham with Pape Matar Sarr was unsuccessful because he didn't have the right to work in the UK during his loan spell, unlike Saliba who is an EU national."
I've no idea how accurate the right to work in the UK part is, as I'm not sure being an EU national now carries the same benefit as when Saliba signed pre-Brexit.
I do reckon that, if nothing else, the club needs to be very careful of ensuring his loan destination still allows him to become CT in future. If we even do loan him out.