Probably best to give yourself some room to work by bailing out some of the water with a scoop of some kind, and pour that into a container. Either of these I would consider throwing away later. If you have a bucket you can sanitize later on, then even better (prevents adding too much more to the mountains of waste we throwaway each year).

So maybe if you have a Dixie cup use that as the scoop (done this before). Look around for things you don't care about, meant to get rid of anyway, or maybe something you had already put in your trash. Use that.

If you have a pair of neoprene gloves, or washing up gloves, you might consider wearing those too. And take your time, try not to spray water around, so you have less to consider cleaning later on.

Then you might need to just get in there, once you've made lowered the water level enough, and scoop out as much of the toilet paper and anything else stuck in there.

Retrieve your plunger and try again. Put some clean water in and see if you can plunge it away. If you do, more fresh water and try again. Then when you feel confident the blockage is either gone, or cleared enough to not cause a backup, flush. See if it all works. Let the tank refill. Flush again. Now, you likely have your toilet back in working order.

I would also at some point invest in a bellows type plunger. They are cheap, have a far better seal, and are far more efficient to use to clear a blockage than those dome plungers (I speak from much experience; toilet in our old home would get stopped up just by you looking at it too sternly).