I don't know if 10% up to 5bbs is beatable long-term. I don't know if should be played at all unless you're getting an incredible rake-back deal.
But for games where we are trying to overcome rake, in addition to the great suggestions above, would sizing up all our opens be helpful to? Like if my opening standard is 3x, maybe make it 4x? Is this a good idea?
Sort of. Sizing up your opens probably has two benefits in terms of rake.
1) You probably benefit from no-flop, no-drop a little more often.
2) If you are being called, the rake will "cap" more quickly meaning the rake will represent a smaller portion of the pot.
But sizing up has the gameplay downside of losing calls that might be to your advantage at a smaller sizing. It's a valid consideration, but it's a give-and-take.
To explain the effect of the cap more, consider a 1-3 game with a 10% rake up to $15 as mentioned above. The rake effectively becomes "capped" at the point where 10% of the pot is $15, or $150 in the pot. Meaning all pots $150 and below are raking the full 10%, and that percentage starts to dwindle when pots get larger than $150 but no additional rake taken.
Examples
$100 pot: rake is $10 (10%)
$120 pot: rake is $12 (10%)
$150 pot: Rake is $15 (10%)
$200 pot: Rake is $15 (7.5%)
$300 pot: Rake is $15 (5%)
This should impact your starting hand selection, unless you are playing a stake where pots frequently go above the cap, in a raked game, you need to fold starting hands that have a +10% EV or less in an unraked game.
So really starting hand selection is a more important adjustment than bet sizing when considering rake impact. But bet sizing is a good consideration too, so long as you don't size up to the point you are encouraging your opponents to play too tightly.