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I found this link for you.
https://apples.ahdb.org.uk/apple-blossom-weevil.asp

Unfortunately, watering was likely the ultimate cause. Staying wet for too long will facilitate a fungal or bacterial infection. I would place my bet on Fire Blight.

Unfortunately, this has no cure, but you can stop the spread. I would recommend, first, treating the soil with DOLOMITIC LIME (you may need to find this online) and WETTABLE SULFUR. This will be the first thing to prioritize is conditioning the soil, which is what this will do.

After this, there are a number of things that you can do. This article will help: https://www.gardeningknowhow.com/plant-problems/disease/fire-blight-remedies-and-symptoms.htm

There may be other possibilities of fungal infection, but since you say your tree has a history of fire-blight, that is the most likely, an advanced fire-blight infection.

Blackening of the leaves and twigs and a "shepherds crook" bending of the branch tips are characteristic signs of early infection. At the early stage you can usually see the margins of the infections and prune out the infected tips a foot below the margins with healthy tissue. This is best done in the spring before infections advance.

As the infection progresses downward into the larger branches it can present as branch die-back. At that stage it is very difficult to eradicate without drastic crown reduction pruning, and it is difficult to determine where the margin of infection is, because it is more internal.

This article will help you with Apple Maggot control.

https://www.gardeningknowhow.com/edible/fruits/apples/apple-maggots.htm

These areas are called burls or burr knots.
It is the tree creating a place from which it can grow roots if needed. It is uncommon in selected apple varieties, but there are some varieties that are prone to it. Many rootstocks get it because they are selected partly for their rooting ability. One of the goals of breeding apple rootstock is to select varieties that root easily, but do not tend to form arial burr knots. They can be a problem. They tend to get larger, not smaller and can disrupt flow of nutrients up the tree, causing stunting or weakness.

They can be caused by bacteria, fungi, insects, mechanical damage, freezing, genetics, graft incompatibility, etc, etc, etc. If the tree grows fine with them, then there doesn't seem to be any reason to try to treat them.

You may also want to contact the garden center you purchased the tree from. They may offer a replacement tree for you.

This depends on if the apple was on its own rootstock, or grafted to another.

If it was grown from its own rootstock (highly unlikely) then the cutting will produce similar fruit.

If this was grafted, then anything that comes up from the roots will be a different tree than the top was. This means that the fruit will not be edible, or may not even fruit at all.

Should you choose to take the chance with the cuttings, this article will help you to do so: https://www.gardeningknowhow.com/ornamental/trees/tgen/how-to-root-cuttings-from-various-shrubs-bushes-and-trees.htm