This lack of a shared reality with the scores is going to hamper lemmy as a reddit alternative if there isn’t some kind of standard or attempt to foster a “true score” across all instances.

No, not really. You should keep in mind that the vote scores on Reddit and other similar forums are fake scores as well. All forms of online voting are fake to some degree.

Reddit also does various manipulations during vote counting prior to showing you a score. For example, they may not count scores from accounts that are too new or has too little other activity, in order to avoid scores manipulated by sock puppet accounts. And it is entirely possible, maybe even likely, that Elon Musk directly controls the vote count on X/Twitter posts to his liking.

So I don't think voting is really all that important anyway. It may be important on centralized websites like Reddit, but it has always been something of a lie. It is just that on a federated forum the lie becomes more obvious.

Personally, I never take voting on the fediverse seriously, and I don't think anyone else should either. I mean, I do upvote, but I use it more as an acknowledgement, more than a means to try to boost someone's comment over others.