Going back to the sell side

 AN1 at a MM. I always thought I'd give banking a fair shot as a career and wouldn't recruit for the buy side but I'm afraid that if I don't recruit and give the buy side a fair shot then my window will close entirely. Here are a few questions:
1. If I recruited and got an offer, but then by the end of my two years in banking I really enjoyed the work and my team, how bad is it to reneg on my offer? I hate the idea of reneging in general and I know the industry is small, I'm just curious how poorly this is viewed.

2. Is it easier to go 2 years IB -> 2-3 years buyside -> IB (as an associate) or 3-4/5 years IB -> buyside?

3. I know that in general, progressing to Senior MD/Parnter level at any IB or buyside firm is difficult, but what you would say are the main differences?

4. If I eventually wanted to exit to a F500, which route is better?

Thank you all for the insight!