I know it's easy for me to say but I would recommend, only spending what you can afford. Your teens and youngest will honestly understand everything single thing you did for them when they are older.
Just be honest with them. This year things might have to be different. You could do one present each or you could do no presents. Do what's right for you.
Limit presents for extended family and friends too. For others you could do one family present instead of buying individually. This could just be a box of biscuits or a book. They will understand. if you tell them. I would hate for someone to get into debt for me. My closest friend earns x 4 what I do. He was still very grateful for a £25 gift card and a M&S fruit box. The old me honestly tried to keep up with what my then best friends were spending, but it got ridiculous. It's honestly not needed at all.
It was my brothers birthday a few days ago too. I didn't get him a present, just a birthday message. Gifts are nice but they don't mean you love the person any less.