How do you root a device with Magisk when it doesn't have a custom recovery

This is a self answered question to address the subject of title. With a recovery in place, rooting with Magisk is straightforward,it gets a tad difficult when you don't have a recovery.This was vaguely addressed in https://android.stackexchange.com/questions/200113/stock-image-dump-for-running-magisk-necessary/200114#comment306071_200114 . So, I thought of making a self answered question to * Help those who don't know and * Add to canonical questions. It's important for our site to have such questions as easy reference (not-so-subtle request to others to post more self answered questions!). **Notes:** 1. I have tried both Linux and Android versions of the answer and they work fine (tested on Pixel 4a, Android 11). The process *may* look daunting but it isn't (I know nothing about Linux, yet managed to root without issues). 2. Moderators are free to make this a community wiki, if more answers are posted depending on the device variants :)