eSIM is a virtual SIM card embedded in a smartphone or laptop. It has a unique IMSI/EID and is logged on the carrier side just like a physical SIM. For phones it's irrelevant; for laptops with WWAN modules — interesting.
Some Windows laptops with WWAN modules expose eSIM identifiers via WMI as additional HWID fingerprint. Anti-cheats currently don't read it, but it's only a matter of time.
Our changer doesn't touch eSIM directly — it's a hardware module with its own firmware. But we do reset Windows-level metadata (modem driver cache, mobile broadband profile) so the OS-visible identifiers change.
If your laptop has eSIM and you're worried about fingerprinting — disable WWAN at BIOS level. Removes the layer entirely.