in essence, civil contracts is an umbrella term for two types of contracts: Contract of Mandate (Umowa zlecenie) and Contract for specific work (Umowa o dzieło). Employment contracts (umowa o pracę), which are its own category of contracts, are the regular employment contracts most people are familiar with.

Basically, the 1 major difference between the civil contracts and employment contracts is that you're entitled to benefits (overtime compensation, maternity/paternity leave, PTOs), work is done in specific work hours (up to 8 hours per day if I recall correctly) and are governed by the Labor Law (at the cost of taxes 😦), whereas the civil contract has none of those and are regulated under the Civil Code, with the benefit of having a higher take-home pay. Oh and either an employee or employer can terminate the agreement at any time under the civil contract.

The changes coming into effect at the start of 2025 concern employers not because this limits the opportunities of foreigners, surprise surprise, they don't give a fuck. They're concerned because this means they will lose out on $$$ that they save from not having to pay those benefits, and foreigners are concerned because this basically limits their options at getting anything resembling a job legally in a job market that's already in the crappiest state possible.

(source: https://polandunraveled.com/types-employment-contracts-poland/)