It's so weird - from the various reports I'm seeing it seems almost random. Especially the people who have multiple devices but it only affects one of them.
Personally I've seen better results since 14.6 and removing/adding my AirTag again. Over the course of today Find My has used minimal battery compared with what I saw over the weekend. My current battery level is 65% remaining, and background activity of Find My has been 25% of that usage... which equates to under 10% total battery used by Find My in the last 18 hours. Whereas the first two nights I was seeing 25-30% total battery usage across approx 5-6 hours overnight from the Find My app.
(Those figures are slightly out, as my phone was last charged to 100% 18 hours ago, but usage shown in Settings for Find My is calculated across 24 hours... but it's close enough and still shows my battery loss due to Find My is behaving a lot better than it was a few days back)
Will be interesting to see how it performs during my testing tonight. Surely this can't be widespread, otherwise we'd be seeing a lot more reports across the internet. It's certainly a problem though.