Removing a chain for thorough maintenance starts with checking its connector. SRAM Eagle PowerLock is single-use: once opened with chain-link pliers, it must be replaced. Opening it only to clean the chain does not change that requirement.
The Shimano manual for CN-M9100, CN-M8100, CN-M7100 and CN-M6100 chains also prohibits reusing a removed QUICK-LINK. It specifies the SM-CN910-12 connector for these chains. A new chain needs a new connector too; transferring the old part is outside the prescribed procedure.
Speed count alone does not establish compatibility. SRAM GX Eagle PowerLock and eTap AXS 12-speed PowerLock connectors are not interchangeable. Identify the exact chain and connector models before buying, rather than choosing a part solely because it says “12-speed”.
Before disassembly, note the chain’s model code and prepare a suitable new connector. This avoids reaching the end of cleaning with a chain ready to fit but no correct part to join it. Leave installation to a mechanic if you lack the necessary skills or tools.