Slow download speeds though having 400mbs+?

I've seen a few other people make posts similar to this on reddit and this subreddit too so I just wanted to make my own. I've got around 470mbs overall on my ps5 and I'm with EE, I'm trying to re install doom the dark ages but I'm met with calculating that's lasting for ages, then when it starts I'm getting 1% that never moves. I've tried clearing my cache and changing dns settings but nothing is working. Showing about 99hrs+ to install the game apparently. I'm at a complete loss of what to do