How do you politely reject someone at a dating app

I have been trying to go to more dating events and get off the app. I’ve been actually enjoying them, seeing them as a chance to socialise and seeing what happens rather than putting too much pressure on the night to meet ‘the one‘

Anyway I went to a dating event last night, had a nice evening and at the end of the night one of the men asked for my number. I gave it to him as I didn’t want to reject him in front of others however I do not find him attractive (I know some people might say give it a chance but I know with me there needs to be an initial attraction or at least a curiosity)

He has now messaged asking to meet up. Previous me would have agreed but I am not looking to waste anyone’s time or people please anymore.

In future how should I handle this (if it happens again) is it better to reject then and there or is it politer to message after saying that on reflection I’m not interested. If it was any other event I would just say I’m not looking to date but obviously can‘t really say this at a dating event. Also obviously it’s easier said than done just to say ‘no thanks’ but that’s a bit awkward and seems rude

I know I would prefer they reject me over text but curious of others opinion or if anyone has any go to phrases