Raj Mehta

Like what Micah said above, the buttons use the same texture as their block counterpart, so if you change the texture of the block then it will change the texture of the button as well. However, you can also create a new texture, and place it in the block textures folder (found through assets > minecraft > textures > block). Then, go back to the minecraft folder and go to models > block, then to the button type that you created the texture for. Finally, remove where it says the block name, and replace it with the name of your texture file. Now you just have to compress the assets file and you should be ready to go!

If you want to switch back to the old snapshot, then first you have to open the launcher, then click 'Installations', then create a new one for 20w13b. This should allow you to play on your worlds created for the snapshots.

This might be because you are playing in the 20w14infinite snapshot, which is part of Mojang's April Fools joke for 2020. If you want to switch back to the old snapshot, then first you have to open the launcher. Then, you click 'Installations', then create a new one for version 20w13b. 

In the newer versions, you have to use the smithing table (대장장이 작업대 in korean) to create netherite tools.

This is part of Mojang's April Fools joke with 20w14infinite. If you switch back to the old version, then it should go back to normal.