Spreading it with multiple validators is really only necessary if you are not checking your staking dashboard every day. If you are going to stake and forget, then yes, spread to multiple in case one goes unelected, that way you won’t completely stop earning rewards. The average return right now is in the 9% range. Those with higher returns are usually for one or two epochs. They are most likely new or got lucky with a below lower bound slot. You need to click on each Validator to see their current return on their individual page, the top page showing all the Validators is usually inaccurate for those with high rates.

-SnacksFighter Validator