About storage is full

Well... that means you have to free up some space. If not, your phone will definitely not work well for you. Your phone does have a slot for a micro SD card so if you haven't got one; get one. Your phone will accommodate up to a 256 GB card.

The problem is this... the memory usually called internal or main in the phone needs to be kept as free as possible because it is the memory available to the device to run the Operating system and the apps that came with the phone as well as any you install. In days past, you could move many but not all of the applications you installed to an SD card if you had one. But it is not so easy these days. Most newer phones use newer versions of Android that usually do not support moving applications to the SD card (Yes Android 12 is one of these). BUT it MAY be possible depending on the individual manufacturer's decisions, to do it anyway. This usually means that you must format your SD card as internal storage, at which point you should be able to put some, but again, not all of your applications on the SD card. First they must be installed to the main memory, but then (if your phone supports it) you can move (some) of them to the SD card. Check your manual as to whether this is supported on your phone. You may need to "enable developer options" and then allow moving apps to the SD card. You might consider getting "SD Manager III" it's available for free, but the Pro version is better to manage your apps if moving them is supported on your device, but if not; I wouldn't bother it can't do a lot for you except take up more space. So... MAYBE you can keep your main memory freed up with a micro SD card by moving apps out of your main memory, maybe not. In any case you can move files to the SD card instead of you main memory, videos, e-books, photos, whatever you have in there that isn't an app or required to be where the app must have it. This will help. Note: if you can't move apps to the SD card you might NOT want to format it as internal storage, if you DO, two things happen that I don't like and you probably won't but may not care... First the card will be useless in any other device, only that particular phone will ever be able to use it, you can't take it out put it in a card reader and move files to it on your PC, nor take it out and put it in another phone should this one die. Along with that, if you ever forget your password and must do a 'factory reset' Your phone will 'forget' the encryption key for your card and IT won't be able to read it either... it will be a very tiny paper-weight from then on. You MIGHT be able to back-up the encryption key in case, but good luck with that. You WILL be able to transfer files to and from your PC in other ways as long as the phone can access it though, wi-fi, bluetooth or USB tethering, but your PC will not be able to read or write to the card (or even reformat it if you format it as internal... your choice. That's avoided by formatting it as adoptable storage, or by formatting it with your PC instead, (consult your manual for acceptable formats).

So... to the things You CAN do:

Immediate steps you can take are to open your "files" app and sort by size, then decide which of those huge files you can live without or move to you PC or upload to the cloud depending on your available apps, Trust of the big companies storing your data on their servers, ahem... You CAN if you're so minded reduce the size of the video files, you probably Don't really need all your videos to be 4K, at least not on your phone. This is doable with free apps and software, but your phone doesn't have enough memory right now to do that, use your PC or (he shudders at the thought) use an on-line service to do it.

Also use the "clean-up option to remove temporary files and cache files. (That's just a stop-gap, they WILL be rebuilt)

AND you might want to uninstall anything you Don't use or need... Especially large apps and/or apps that have lots of storage taking up space in the main memory.

Do be aware that not having upwards of 20 percent or so of your memory free, and this includes your SD card, with cause things to slow down... try in the future to achieve at least that...

Have Fun and...

Good Luck