First off, see if it is actually your SSD that is slow. Install Blackmagic Disk Speed test to see how your drive is going(speed wise). If your drive ends up being very slow(compared to what it is supposed to be), try erase your drive completely(make sure to backup all the files you need). Then reinstall MacOS and try run Blackmagic Disk Speed test again, if it has become faster you are good to go. If it is still very slow in the test, then consider switching out the SSD. The MacBook Air you linked does not use a SATA SSD(as far as I know), it uses a custom Apple SSD(Not m2, there are adapters, but they can be unreliable). Consider following this guide to replace it, and if you really want a reliable drive option, purchase the drives that IFixit recommend.
