Quote
a bottle of Prednisone

Probably saved your life. One of the keys to successful treatment is NOT to give steroids early on, because they decrease immune response and that can make an infection worse. But by the time you get to the hospital passing out from low oxygen saturation, most of the virus is "dead". Those symptoms are immune system over-reaction which causes almost all Covid deaths. The doctors probably had no idea what you had, but ran some simple blood tests and found a very high C-reactive protein level. That indicates inflammation, and steroids are the best treatment. Fortunately for you, WHO had not told everybody not to give steroids yet.

For most everybody under 70 and with no comorbidities, a fourth shot is unnecessary. You WILL get infected if exposed to the latest variant, but it will just be a "Covid cold" and act as a booster. For people with more things that make it likely to be serious, a fourth vaccine will boost your antibody level for a few months and make even that "Covid cold" less likely. But a fourth shot is very unlikely to cause any harm to anybody who did not have a serious problem with previous Covid vaccinations.

For vaccinated people with a working immune system, there is this thing called "somatic hypermutation" that makes antibodies against a wide variety of variants. Even against SARS1 and MERS, as well as every possible future variant. Not a lot of each antibody type, but enough that you have some that will react against a new variant and start the immune system cranking out new variant-specific antibodies quickly. This is why a new "Covid cold" acts as a booster for most people.

Of course, the real "star of the show" is T-cell and B-cell immunity. Those are much longer lasting and much more resistant to "immune evasion" than antibodies with new variants. Antibodies react to a much smaller region of the virus (an epitope) than T-cells. So a few mutations in a new variant can make the variant evasive to old antibodies, This is why so many monoclonal antibodies are no longer effective. T-cells react to a much much larger viral epitope, so several mutations don't affect them.

Educating anyone benefits everyone.