Not sure about those symptoms/behaviours maybe contact health visitor? As for the getting up in the night we started doing a reward chart with my daughter just after she turned 3, this worked really well, she got a sticker for things like brushing her teeth, getting PJ's on, going to toilet before bed, going to bed on time and staying in bed all night, at the end of the week if she got all her stickers she got a prize. Give it a try she actually stopped getting out of bed at night when we did this and she willingly did the other things without the usual fight. Also if she's regularly getting up for hours at night it might be time to drop her nap.

Im not usually one to scare monger but I’d be really careful about letting her sleep with a mouthful of bread. Chewed bread is a huge choking risk.

It's kind of the luck of the draw. My DD1 was an unholy terror with tantrums from 2 til about 7 and between 7 and 11 was pretty hard work. She would scream and shout and it was at times unbearable. 11 onwards she was like a different child. Pleasant, funny, smart, helpful- a joy to be around. Like a switch flipped. She is 17 now and a joy.
Dd2 was chilled out and very easy (until she was about 13 when all hell has broken loose in very teenage fashion).

Once you have ruled out anything medical (looking back we realise dd1 had recurrent ear infections-which might account for some of her behaviours-she was diagnosed at about 7 with an ear issue which she had an operation to fix-but I don't think that was the reason for all of it) it might just be the child you have. In which case, firm boundaries, tag team with your Dh so you both get a break, carry on reinforcing good behaviours and hope it comes right.

It's tiring and hard work.

I agree. This was my first thought/concern

Luck of the draw mostly, I'd say. My first born was like your dd. Took years of work but he's a great kid now. The middle one had two tantrums her whole life. The youngest never tantrummed at all. Nothing to do with us as parents, and everything to do with their personalities.

DS, to settle himself, liked to chew on knots, so we got him a bunny comforter that had knots for hands and legs and he would chew and chew and chew to get to sleep (was never interested in dummies). He used to chew the arms right off so we would have to replace them, lol. He was also a horrificsleeper - would only nap for exactly 25 minutes at a time, would wake every hour for several years and would be up for the day at 4.30am. He slowly, slowly, grew out of it and sleeps just fine now.

It sounds like she has a high sensory drive. See if you can find her fidgit toys that are age appropriate and something to chew on that she cant choke on (like a teething toy) but its good that she has some self soothing strategies.

What are the triggers for her tantrums? Is she tired, hungry, overwhelmed with too much noise/lights/instructions, is it transitions…. If you know what some of her triggers are you can head things off at the pass.

Once she is in a tantrum, you need to leave her be to work it out of her system. Is there a safe space you can put her? Night time tantrums are harder as she might wake her siblings, I would be tempted to make a corner of the downstairs her safe space (hopefully you have somewhere quiet away from everyone - maybe by the front door?). Show her the space when she is calm, put a blanket in it and some sensory toys that have to stay there and tell her it is her own special calm down spot. Dont let the other dc use it.

When she starts to unwind, take her there and say she has to stay until she is calm and can sing the ABC song (or something similarly silly) be really really consistent. You might find that she will start to notice herself starting to get stressed and go there on her own.

The last thing is that you need to never, never give in to the tantrum (so she doesnt get the blue plate/biscuit/no shoes) otherwise the tantrum becomes about controlling you and not her loosing her own control.

I’d be more worried about the bread, OP

Ditto concern re the food - I would stop this. Tantrums daily of 30 mins to an hour do sound quite excessive and I agree with others re is there some sort of sensory issue going on? I'd discuss with GP personally.