I will prove to you that God exists

[Sheldon]

It isn't erroneous. They're two entirely different hypotheses. One is one possible explanation for the other but neither one affects the other. The multiverse hypothesis could be entirely disproven without ever affecting fine-tuning and vice versa.

Hypothesis such as multiverse or cosmic inflation are thought of as an explanation for an observed phenomenon. Of course even if the hypothesis is disproven, the observation that led to the hypothesis is still persists...why wouldn't it? I do agree that multiverse is a 'just so' time and chance naturalism in the gaps argument.

Nope, more projection, it is an objective fact that natural phenomena are possible, it is an objective fact the material universe exists, it is an objective fact that life emerged, and then evolved...

Now we have a gap in those facts of how that life emerged, and along you come to wedge your deity of choice into that gap, tadah - using inexplicable magic, except none of it can be demonstrated to be possible.

You're violating Occam's razor, so much for you being a philosophical theist.