TL;DR: Still open - see below.
This morning I woke up to some not-so-nice surprise - my 2018 MPB 13" would be kind of totally unusable. The accountsd process was stable at 400%, battery was going like ice-cream in the Sahara, and opening up LibreOffice was like a major achievement.
I did check the logs (that were growing at like 500 lines per second) and I saw a lot of lines at FAULT level:
fault 07:54:04.271342+0200 accountsd Unentitled access by client 'CallHistoryPlugi' (selector: accountsWithAccountType:handler:)