Yeah, I agree that at the very least this consideration shouldn't get swept under the rug.

[epistemic status: mulling over my moral intuitions in realtime, almost certainly will not endorse this upon further reflection]

When Many Worlds, Big Universe, or "Lots of Simulations" comes into the picture I become very confused about how to aggregate experiences.

But my current best guess intuitions are:

suffering adds up linearly (but if suffering exists in insects or bacteria or other Brian Tomasikian considerations like simple feedback loops, it doesn't make sense to deal with that until humanity has their collective shit in order, and can think real hard about it). It is always morally commendable to reduce unnecessary suffering, but not always morally obligatory.
positive experiences add up less linearly, and "variety of positive experiences" matters more.

I have some sense that the positive experiences of rats adds up to a finite value, which I'd guess is greater than the value of a single human but less than some finite number of humans (whose positive experiences can converge on a higher finite number because there's a wider variety of experiences accessible to them)
By contrast, if bacteria had anything that I'd classify as a positive experience, I think it'd cap out at less valuable than one human.

there almost certainly exist beings whose capacity for both positive and negative experiences exceeds humanity
some degree of contractualism matters, which includes acausal contracts I might wish I had made with simulators, in this universe or others. I want to have some kind of consistent contractual policy, in which simulators or aliens who are more morally valuable than me still have contractual motivation to treat me well (in return for which they might be treated better by other hypothetical simulators or aliens).

I think this implies making reasonable efforts to treat well beings that I think are less morally valuable than me (but where "reasonable" might mean "first get humanity to something approximating a post scarcity shit-together situation")