When he stopped being trapped in the speed force. When Wally took his place.

Agreed. The previous one was actually quality for the first half—characters, story—then it jumped the shark.

Logan is a good counter point to this. Or the exception that proves the rule.

The usual ways, sure.

What kind of hacker just plugs in a USB stick from a stranger directly into their primary computer???

Adjusted for inflation, $10,000 in 1958 is equivalent to $82,000 today. Sounds pretty nice independent of gender.

And that's why when he appears in Arrow crossovers, he basically just provides a deus ex machina function.

I can't speak for the UK, but in Canada, we have the 'mum' pronunciation, but for spelling, both 'mom' and 'mum' are used for it.