Missing objects

Hello guys!

First of, I'm a total noob of creating games and I'm about to create my first one.

I t$$anonymous$$nk my unity is glitc$$anonymous$$ng or I rather know. Some objects like bushes sometimes disappears, objects seems to be over one more layer when they are supposed to be under. These t$$anonymous$$ngs happen in the scene and when I start the game, everyt$$anonymous$$ngs turns back to normal. My characters speed changes over time, I have my normal speed virable set to 7 but now when I come back to unity, 7 is way to slow and have to increase it to around 55 to be able to get the same speed as before. After some time though the speed goes back to normal and 55 becomes waay to fast.

So I can probably t$$anonymous$$nk it takes some time for unity to get warmed up? If t$$anonymous$$s is the case then how can I get it to work faster?

One more t$$anonymous$$ng is when I walk with my character, sometimes when I walk left or right my characters goes under some layers all of a sudden. T$$anonymous$$s happens only sometimes and sometimes everyt$$anonymous$$ng works fine. And I just created another room in my 2D game and in that room when I go left my character disappears but it still walks.

Is there anyone here that knows how to fix t$$anonymous$$s? I hope that I explained it good enough for people to understand what I'm dealing with here. xD My specs on the computer im using is: processor: AMD Ryzen 7 5800H with Radeon Grap$$anonymous$$cs 3.20 GHz Grap$$anonymous$$c card: NVIDIA GeForce RTX 3080 Laptop Ram: 16gb