There’s multiple installation methods for magisk, the one that works with an SD card is the custom recovery method. You have to download the magisk app apk, rename it to a .zip, put it on your SD card, then go to LineageOS recovery, install update, chose from [SD card name], and then install the magisk update.
There’s multiple installation methods for magisk, the one that works with an SD card is the custom recovery method. You have to download the magisk app apk, rename it to a .zip, put it on your SD card, then go to LineageOS recovery, install update, chose from [SD card name], and then install the magisk update.