We have a local privacy podcast (Dasprivé). The CISO was featured on the podcast. I can't transcribe everything but the community consents on the fact that they run a tight ship. The use case is very local so apart from Flemish and French speaking sources i sadly can't get further than 'trust me bro' at the moment.
Every authentication uses your SIM, your civil service number and your password (PIN, fingerprint, face id). Before authenticating you'll see all the info that'll be shared like your, date of birth, adress, phone number,...
Acces is granular. If age verification is needed, the request will only state that you're 18 or above for example. They don't get my date of birth. As a resident, I get a reduction at our local swimming pool. The can use my id but the only info they see is whether I live in the city or whether I'm from outside.
Everytime my data is accessed, the acces is logged. The log contains information about the organisation and, if it applies, the person that made the manual lookup. The legality is checked by logging the legal ground for acces.
Are they trustworthy? I don't know. We use our eID for online verification for over 20 years now and ItsMe has certainly made the whole process a breeze.