Here's an idea: only do the missions with timed rewards that you need.

That is a great idea, if you don't want to progress in some other way. Let's say you need to rescue survivors at 46+ and there is a rescue survivor mission at 46 and only that, with planks of wood. You can either save a couple of people across multiple missions or possibly do one mission, at the cost of your one timed reward, so you can progress faster.

This stuff is one of the biggest issues with Fortnite. Almost everything has an opportunity cost and that can get frustrating/discouraging. You can do story missions you need, often at the cost of resources you don't want, or do missions for resources, potentially at the cost of experience and/or story progression.

Unless you have absolutely no interest in progressing in anyway in Fortnite, you basically have an endless stream of chasing specific resources, making calls on timed rewards, deciding to progress in the story or holding back and this stuff wears thin after a while or at least does for me.

Today I signed on to get research points and clear out one of my dailies so I can get one today, saw an epic pistol schematic (don't like them, but might be helpful to have), but ultimately opted out of even trying. Not just because no one was playing at the time (I loaded up six lobbies and waited a minute and 30 seconds), but because the idea of doing a mission that had nothing to do with any of my three dailies, for a reward I barely cared about and would ultimately take me multiple rare schematics I don't really have and more rain, was just not thrilling.