Letting them down gently?

I’m back on the dating scene and having trouble with telling guys I’m not interested anymore. I had a couple get very aggressive in the recent past so get nervous with this but I feel bad just ghosting.

None of these were serious or long term. Maybe just texting or 1-3 casual dates. These are largely professionals aged 36-44. Levi’s text because of the casualness of the relationship and my general valid fear now of violence.

Apparently the middle ground of explaining I wish them the best without an explanation in detail angers them but if I give one good explanation (schedules don’t work out, etc.) they keep coming back or argue and try to force it and will not take no for an answer. Does anyone have a good standard “no thanks” text that gets the point across? Maybe it’s how I’m wording it but these are the same things I used to say without it becoming a fight.