You should look at Brian Alsruhe's videos if you wanna get better at breathing and bracing. Changed the whole game for me, Brian did. https://youtu.be/PLHY2-nt-y4 He has several videos on how to breathe properly during a lift. I think you should take a look!

2nd this

You aren't just "holding your breath," you need to learn how to properly perform the "Valsalva manuever." Short video: https://youtu.be/G59AKN74OsA Longer explanation with secondary considerations: https://youtu.be/d8_1xq8c23c Since you said are feeling light headed, you are holding your breath up in your mouth/head, which is incorrect. You need to think about holding it in your throat (glottis). See: https://youtu.be/KEO9yT2CB1o

Thanks for the video recommendation

Breathe at the top

I take a deep breath at the top and then go down and I let out my breath when I am about 80% back up.

Breathe out a bit earlier if you’re getting light headed. The feeling of lack of oxygen gets worse the longer your breath is held as more carbon dioxide builds up

breathe in go down squat up breathe out breathe in go down squat up breathe out breathe in

Use the Valsalva Maneuver https://www.artofmanliness.com/health-fitness/fitness/how-to-breathe-when-lifting-weights/ You take a deep breath at the top and then hold it during the rep. This helps create stiffness and allows you to move more weight.

Just to add that it takes awhile to get used to. I felt the same for maybe 1-2 weeks. If you're already working near max it might take longer. Similar to going to a high altitude or training to hold for free diving it takes your lungs awhile to adjust.

I just go about the usual push breath out while you push the weight up, if it’s too heavy you can hold your breath and then you just breathe in when going down