Excessive power drain, with Siri as culprit?

A while back I fixed an iPhone SE 2020 (new bare housing and replaced screen with a refurbished genuine Apple LCD display) but didn’t sell it due to battery concerns. I am now in the process of testing it and settings is revealing Siri as a major culprit.

It lost about 10% last night with sleep focus mode on, and settings is reporting Siri used about 50% of the battery, however, I have never once used the assistant on this phone. I have just turned Hey Siri and Home Button to activate Siri off and will see how that goes, but this seams to be a somewhat common issue and wanted to see if people had a fix?

The iPhone is running iOS 15.5 (latest). I look back at screenshots taken in April when I tested the phone and it shows that Siri was not at all the cause of battery drain (Apple Music was). Hence, I hypothesis it’s the update that has caused this.

I am hesitant to replace the battery with an aftermarket one as it reports 89% in Settings and about 90% in Coconut Battery (which also indicates the cell is less than two years old (and has only really seen use for a bit over a year) and only has 300ish charge cycles).

Any help and suggestions will be much appreciated (: