Most of the Ikea faucets are made in China by various manufacturers, and 
many of the Chinese cartridges are standardized within China.

The Apelskar bathroom faucet uses a common Chinese cartridge which is an
adaptation of a Kohler design.  I don't know if the Kohler cartridge will
fit, but the Huashan part X001U7818L will fit.  This is a 1/2" X 53mm
cartridge with a 12mm spline length.  Example would be:
https://www.amazon.com/Huashan-Replacement-Ceramic-Cartridge-Quarter/dp/B07FM9DZF3

Notice that there are several Huashan cartridges with the same diameter but
different threads.  The X001U7818L seems to be correct.

The Alsvik faucet uses an all-plastic cartridge which appears to be
a Kerox KN-35A copy... the K35A will not work.