If you get a steam deck, you can format it and begin installing a game, but it will take a long time. It was like, "Is my internet broken?" There seems to be something happening to some Deck owners that is preventing them from being able to operate at full speed.
You will lose your game installs and anything else you have stored on your card if you don't reformat your card quickly, but there is a fix for it that doesn't take a long time.
There is a caveat that it is possible that your microSD card is slowing things down. Alice Newcome-Beill told me that I should buy a card with a U3 write speed and an A2 application class because it has higher random read and write speeds. Some people get fake microSD cards that don't have the capacity or speed they're advertised to have.
Here is a smart and well- documented solution to this problem that worked for me, if your model doesn't meet that recommendation. Thanks to a user named RoyalMetalKnights, it can be found in the steam forums. It doesn't take a long time to do.
I will post it here for easier viewing and to give this good advice to someone else. I have made slight changes to the wording to make it clearer for beginners.
The steam deck needs to be powered on. It is a good idea to make a backup first since you will be completely formatting your card. You can copy and paste the contents of your microSD card into a folder on a computer or a cloud storage service.
If you hit the hardware button, you can select Power and then switch to the desktop. The logo of the steam deck can be found in the bottom left corner of the screen.
On the left side, select the system and on the right, select the partition manager. The feature was pre-installed. Take note of the two options that are displayed under Devices, one of which will be the name of your internal storage device. For example, my 64 gigabytes of storage says "E2M2".
The choice should be made by default. Select if it's not. You can see a visualization of your partition on the top right of the screen. There should be a blue box next to ext4 and under type to make sure that the correct storage device is selected. Something similar to your microSD card's capacity should be reflected in the size storage space shown.
Pull the lefttrigger to show a drop-down menu if you want to hover over that bar. You can select unmount. While hovering over the same spot, press the lefttrigger again.
At the bottom of the screen, in the Pending Operations box, it should state that the partition should be deleted. Go back in the process if it doesn't say "delete" In the top- left corner of the screen, look for and click the button that says Apply, if you have confirmed that it says uninstall partition.
The pop-up will ask if you want to do the deletion operation. You can apply pending operations by selecting the button. Press OK once the operation is done. The words Unallocated and Unknown will be shown in the middle section of the screen when partition information is displayed. The drop-down menu can be brought up by pulling the lefttrigger. From the drop-down menu, select new. Change the file system option to ext4 and you'll be good to go. The program has a button in it's left corner. There will be a pop up. You can apply pending operations by pressing the button. A new ext4 partition will be created in about 50 seconds. You will get a Disk & Devices alert when a new card is inserted. If you want to close the app, hit the X button at the top-right corner. Double-click or tap the Return to Game Mode icon on the desktop to return to Game Mode.
Go to the settings and click the hardware button. Click into storage if you scroll down. You should be able to see your internal drive and card. The gold star next to the card is the default installation drive. Hit X to make default if it isn't. After installing a game, you should be able to see the progress, download speed, and disk usage speed on the Downloads screen.