Legion 5: not too difficult to open up but some of the tabs are comically flimsy. I used iFixit tools (not even my nails) and the tabs that broke were not pushed
DIY - replace hdd on ssd Lenovo Legion Y520-15 and Upgrade ram DDR4 to 8GB or 16GB,DIY tourtial - YouTube
Lenovo Legion Y520 review - bang-for-the-buck gaming laptop at under $900