Actual engineer who ran the numbers: if you are creating a JOG, then TWO 90s replaced by TWO 45s does create slightly less back pressure. However, ONE 90 replaced by TWO 45s has almost no impact. it is only when replacing one for one that it matters. Two 45s for one 90 isn’t a savings.
On the topic of pumps, look at the flow chart if you can find them. Some pumps actually run more efficiently with a certain amount of back pressure. This has to do with the impeller and housing geometry. Not all pumps are the same. However, I’ve never seen evidence that adding some restriction to control flow rate slightly has any impact on pump life. Other things like keeping things clean to prevent fouling or damage are more likely to destroy a pump. Back pressure that the pump is designed to work against, not so much.
Happy Reefing.