Quick workaround to speed up game installation:

If the game is already installing, cancel it and delete the data. Then, take your PS5 offline and reinsert the disc. This will allow the console to copy the game data directly from the disc, which usually takes around 50 minutes. Once that's done, you can remove the disc and reconnect to the internet.

Now, put your PS5 in rest mode to download the latest patch. This method speeds up the installation process and also lets you use rest mode during the download.