I live in a two room flat. My mother lives in the other room. Her room has our DSL connection and therefore she has the internet Router there. But I want to get the router inside my room because I want to play around with networking, selfhosting and a NAS. I don't own this flat and don't want to make a hole in the wall to lay cables. My idea is that I use a 5m DSL cable that I will place along the wall and under both her and my doors inside my room. Then I can place the router here. Do you think this would be a problem for internet speeds? I read different opinions on this. The other possibility is that I buy a flat ethernet cable (hoping it will fit below her door which only has very narrow space there) and a network switch, so that I can connect all my stuff this way to our home network.

Which one would you recommend over the other? I hate that I need to lay cables below doors and do janky solutions but this whole flat sucks anyway yet I am stuck here for at least the next year.