I'm actually pretty sure I covered all your points, just out of order.
Yeah it does fail, good job igniring the rest if the statement abd why it failed though.
Yeah a limit was shown, spaceship is likely too much, a city is fine though as shown by her lifting the monster base.
The hell? How in the hell is it? She left the regen alien up to the others and focused on taking down the ship, is it really that hard to understand?
Yeah it doesn't, and your right, i am gonna say because its Saitama, thats clearly, obviously, why it didn't work. Ya think her tossing dozens of city blocks, lifting a city and more yet her failing to lift Saitama 5 feet off the ground is an argument for her straining to BFR? No its because its Saitama, hes not actually heavier than a city, but because hes so far above her the tk aint doing shit. Also in that case with him, she wanted to prove her superiority over him, BFR aint proving your strength and heroism is better than him.
Youre right, she never did end up using bFR, but context matters dude, hence why i asked ya to find an instance that makes sense for her to do so and it being someone that isnt a thousand times stronger.