Thanks guys and sorry for not giving an update sooner… life and stuff. I tried doing that but turns out the router form my IP has very limited configurations and has to be done through their webpage etc. They claim it’s because of European data protection laws but that’s porbably nonsense. I had to ask around on national forums how to even try to configure it.
Anyway, I think I ended up not changing anything, just identifying my PC as a PC which was listed as an unknown device connected to the router. I don’t know if it was that or a windows update that came in this week, but the IP is no longer changing.
I’m very suspicious that this issue got resolved as I couldn’t pinpoint the origin and I’m not sure what I did or didn’t do to resolve it. I will be keeping an eye on this and probably getting a better router as aparently it is possible to have the one the internet provider issues just as a modem connected to a more manageable router. Hate to pay for something that a company then treats as their own stuff and doesn’t let you do anything with it.
I’ll mark this thread as solved and if the same thing happens again, I hope that at least then I can ask for help in more elaborate way. Thanks again for the help!