Do people still use Goldenline much? I remember it was a thing about 15 years ago.
People who use facebook tell me that there are pages for expats in Poland where there are people who speak English from dozens of countries, many of them students and those pages have jobs advertised as well as job seekers on. That might be a good bet to find somebody.
I use OLX for advertising for interns - get fairly good response rates and it keeps junk out of your email inbox. Be very clear about what you need - if they have to speak English or have tech experience.
And be prepared for some appalling standard of replies - the quality of applications and manners has gone south since Covid and you will have to pay about 25 zloty an hour for an English speaker.