I use Stremio and only stream full 4K Blu Ray rips, with HDR and Dolby Atmos and all. So nothing is recompressed. 50-70GB files but it starts streaming almost instantly.

I have a poor 5G signal due to a tree that's blocking my view of the antenna, so I get anywhere between 400Mbps and 1400Mbps (I'm supposed to get a gigabit but it's usually closer to 500). Even with a poor signal it's still way faster than any other ISP in my town.