Given that you performed a speed test and showed you that there is no internet issue, I believe the slow downs during in-app downloads is not due to your phone's connection problem but rather the game servers is putting limits to download bandwidth per user. It is usually done to prevent the server from overloading especially when there is a major update and all the users decided to download all at once.
So, as much as we want to help you, we can't actually do anything to make it go faster. Me, myself, have already experienced this slow in-game resources download before when i first installed CODM here. It was fast using the download in playstore however when i downloaded the remaining resources in game, it was painfully slow. We just need to be patient while waiting for it to finish. 😁😅
It probably depends on the signal strength of the game server (something like that). Are you not using VPN to fake your location? Choosing a father region can also affect loading speed.
The game's servers are different from Play Store's servers, so the slowdown you're experiencing is likely from your game's servers not having the bandwidth to support faster downloads / lots of requests at a time.
Unfortunately, short of donating $$$$ directly to the developer to purchase some new servers, there's not much we can do except wait 😅😅
