What to do? Great dog with rare but insane biting attacks

tldr; wonderful dog has started biting, unpredictably and very infrequently (every 6 months) and after having spent 24 hours at the hospital and plastic surgery last night, I need advice.

I have a 6 year old dog that I adopted from kijiji when he was 9 months. At that time, he lived with a family with 3 kids under 5, and they kept him in a crate all day because he was very nippy (Corgi puppy, typical baby landshark behaviour). They got rid of him because of this. He grew out of the playful nipping by 1.5 years.

He is a very typical Corgi in a lot of ways. He only wants to do something that he knows you want if he sees the treat first. He is easily spooked (when we got him he wouldn't even walk past a mailbox on the sidewalk) but he has improved a lot. However, he is still freaked out by a curtain blowing in the wind, a photo mobile shifting, a ball landing on fabric that slowly compresses, the screensaver on the TV.

He is affectionate on his own terms. He will jump up next to us for rubs every evening, but he is also a little motor, so plays fetch a lot indoors and then when he is tired lies down next to us. He licks us constantly when next to us, but will not sit on our laps except for boots before walks, is crate-trained, does not resource guard (you can take food out of his bowl even while he is eating) and is perfectly house-trained.

That said, there are some things we cannot get him to do, like walk peaceably past a large dog (goes nuts, but around people and small dogs is good) or let us pick him up when he knows the next place he is going is to bed in his crate. (Instead we take him for a late night pee, pick him up to wipe his feet, give him treats, and then carry him to bed.)

This long description is to give context to what happens next. In the last few years he has started biting (7 times in 3 years).

1. The first time he was in the crate in the morning. His daytime minder came to pick him up and he didn't run out like normal. The minder reached into the crate and he bit him. I attributed that to a one-off that he was feeling sick and told the minder never to reach into the crate; not that the dog should bite, but if he doesn't burst out of his crate when it's opened, it's very weird, and it means he's sick.
2. My daughter, home from university, was trying to put his sweater on before a walk in the rain and grabbed his leg to put it into the sweater and he bit her. I attributed this to her inexperience because we do not grab his feet to get them into the sleeves, we move the sleeves around the feet.
3. I had dropped him off at the minder before going on a trip and the minder picked him up to take off his boots, and grabbed his foot to do so, and he bit him. The minder had not ever used boots (I had walked him there in the rain and forgot to deal with that myself). The minder was freaked out and gave up minding. But after that I told everyone, leave his feet to me.
4. The next time I was trying to pick him up to put him in his crate because I was not able to do it straight after his nighttime pee. He was fleeing and when I went to grab him, he did not just reflexively bite, like he did the other times, but actually turned on me snarling and chomped me hard and more than once. At this point I was shocked. But it was an unusual situation and I wasn't sure what to do or think.
5. He was sitting on the couch with us, being his normal sweet affectionate self and getting tummy rubs from my husband and out of absolutely nowhere he savaged his hand leaving a scar. I thought my husband must have hurt him accidentally. I brought him to the vet and the vet could not find anything wrong with him or any sore spots.
6. A couple of months ago, I got home from work early and he was in his playpen in the semi-dark in the basement. He got out of his bed and came to the edge of the playpen so I reached down to pat him and he suddenly bit me while snarling, looking at me like he was a crazed dog in a horror movie. I got my hand away with just one tooth puncture but it like a switch flipped in him for a few seconds. I ran to put water on the wound and when I came back he was so guilty and apologetic. I thought maybe I had woken him up and he was still semi-asleep or having hypnogogic hallucinations.
7. Last straw? Last night, I was down on the floor smelling the carpet trying to figure out why it smelled like dog when I had cleaned everything and the dog had had a bath a week ago. We had just let the dog out of his playpen after work so he was very buzzy, racing around. The carpet smelled fine so I stuck my head into the dog's side to smell him to see if it was his fur and he totally freaked out, snarled like a crazed dog and clamped his teeth into my face and held on like a dog shaking a squirrel. I was at the ER overnight and had to go to plastic surgery today. I just don't know what to do or think. I am extremely grateful he did not hit my eye, and that this happened to me and not my daughter or a dogsitter. He left deep teeth marks on my jaw and neck that required stitches, and my lips are lopsided till the facial nerve heals.

What should I do? (It is pointless reaming me out for letting this pattern develop.) I just want to know what I should do NOW. I feel like I can't keep him. But I also love him and feel so sad for him because he's like the best dog when he's not in these insane moments. But he also feels like a time bomb, and anyone looking after him, for literal months, would say he's the best boy. Until suddenly, briefly, he's not.