how do u make ur pixel art so high res ?
I'm still learning myself, but this is my process! I even forget to change the settings to "hard edges" sometimes and it still comes out fine. I usually bump the scale up by 10, but that really depends on your canvas size. Mine are around 480 x 270 pixels usually and then x 10 for resolution. I imagine you can use this with any program that allows you to edit the resolution.
Here are a few tutorials I found that could be helpful for step by step assistance:
Pixel art resizing discussion
^ if you are interested in the thought process of pixel art and someone who is just genuinely passionate about it, I highly recommend watching this channel. They cover a lot regarding pixel art and analyze retro games.
How to scale and resize pixel art
I've never used this before myself and just found it today, but Lospec is a website full of resources for pixel artists. It even has a place where you can drop your original pixel art and scale it up without having to worry about blurring! Here is the page
Additionally here is a video covering free and paid programs that could be used for pixel art or are specifically made for it!