Also one difference is that The Ukrainians only let children and women leave the country. Men 18-60 are not allowed to leave. So the people coming over are truly vulnerable.
No, that's not a difference. Poland has been preparing to welcome Ukrainians long before the invasion started. It had opened up its borders and had logistic ready to receive them as soon as Russia invaded.
All of this happened before Ukraine closed its borders to fighting-age men.