Does the Live RTP information on website A align with other websites featuring the same provider and listed games?
It can be yes or no, depending on the data source. For example, Live RTP on Bitcasino.io and Sportsbet.io is the same, since both use the same data. These sites are actually the same site with different skins and names
This is an example of the data being gathered locally, only from their casino server. You'd probably find other casinos/websites that utilize the same data, these are basically mirror sites.
There are other casino groups that collect live RTP info as well, but different groups will have different sets of data since the data are collected locally in their casino server.
So the Live RTP data is only measured from the particular website/casino group, and it might or might not be drastically different from each other as it's completely random.
Here you can switch between casino providers:
https://slotcatalog.com/en/Hot-Cold-Games (I don't vouch for anything including the validity of data, DYOR & DWYOR)
maybe when I decide to play again one day, I will choose a website that provides live RTP information. In this way, I can share my experience for the results when playing games with live RTP informations with without knowing the live RTP and it will be the first one I'm trying more than 1 casino.
Live RTP information is only a myth as it only measures historical data. Moreover, you'll find some of the data isn't big enough since they often didn't include how many spins. For example, we cannot say if Gates of Olympus (for example) which has 200% Live RTP from 100 spins is in a hot state.
Anyway, there is a site like Alexa in the past that collect information from a browser extension like:
https://slottracker.com/ (I don't vouch for anything including the security of the extension, DYOR & DWYOR), if the site and extension are legit, the data from this site is more meaningful since it includes the number of spins, and gathered directly from the user.