I think you are really neglecting how long billions of years are, but the universe in this case just all the stuff we could ever affect and that could affect us. There have been lots of discussions about stuff outside that - what physics might have caused a big bang, or happen outside it, and how many such worlds there are, even whether they have been evolving.
You might enjoy some of it. The problem is that none of it can be physics per se, since it’s musing about what is inherently beyond any check of observation. Whether it even makes sense to say that stuff exists or not is a question of your ontology. At any rate: this is the origin our universe seems to have, and if it seems to small for you, the better answer is to look for more universe beyond it.
That’s an odd thing to suppose, though, because it’s not like physicists always insisted on a finite age. The uniformitarian idea things are infinitely old predates the big bang; there are problems with it, such as Olbers’ paradox, but people did propose solutions, notably the Steady State theory. Some people even clung to it for a long time out of dedication to the uniformitarian idea that the universe is not aging.
The reason the big bang ultimately won out is it gave the best account for the evidence: the redshift of galaxies, the cosmic background radiation, and so on. There are some difficulties in expansion rates, which is what inflation was meant to reconcile. But it seems strange to me to claim it is nothing but shoehorning evidence into a poor model, when this whole story is about people working to test a prediction of inflation.
Nothing in inflation or any other versions of the big bang theory necessitates an edge, and most people have not supposed there is one. The explosion is not so much outward movement but one way of distorting spacetime, so that the distance between “non-moving” points increases over time, as described and actually predicted by general relativity.
This could happen to an infinite plane, or a finite but edgeless universe like the surface of a hypersphere, just as easily as it could happen to one with a boundary. The only thing that the Earth is in the center is the portion of the universe observable from Earth, but it is supposed any other point would see something very similar.
It annoys everyone, I expect, but that’s not something particular to talking about the big bang. Physics in general seems to suspend the “normal rules” when you start talking about sufficiently small distances and times. A good theory of quantum mechanics including gravity is still being worked out, but we certainly know that things like well-established relativity stop being good approximations.
Fundamental particles are ones that aren’t themselves made out of smaller pieces, but they might still be able to be converted into ones with less energy. I’m afraid I don’t know the supposed details for Higgs bosons very well.
A more familiar example, though, is the W- boson, one that carries weak charge from particle to particle and so changes their type. So for instance an electron can become a neutrino by emitting one, and combining one with a neutrino gives you an electron. But it is too heavy to be stable on its own.
The reason is absorbing a particle is also the same as emitting an antiparticle, so a W- by itself could turn into an electron and antineutrino. Those aren’t inside it, and in theory it could also decay into other pairs, like a down quark and up antiquark. But they’re the lightest option, so they’re what you tend to get; in fact this is thought to be the basic mechanism of beta decay.
Is that of any help to anyone? I wish I could also address any of the things said by “Hannes Alfven”, but then I have tried before to no avail. He talks a lot about how modern science is all myth or dogma and how useless peer review is; but at the same time he is happy to quote other things with almost no evidence at all, or straight-out wrong, even Velikovsky’s junk-science-supported-by-junk-history.
And for all the complaints about peer review, he has not previously answered any questions about what standards of evidence he would prefer. So he seems to be much less about finding better ideas to avoid dogmatism, and more pretending uncertainty for creationist-style “teaching the controversy”. His history is all the same set of talking points on one topic after another, plus a Gish gallop where one claim is easily replaced by another.
And just as I wouldn’t discuss biology on a board where young-earth creationism comes up each time, it really makes it feel like it isn’t worthwhile to bother with physics here. I don’t know if that’s anyone’s problem but mine, but I thought I ought to say so before giving up. 
