You don't have a tech problem (yet). What you have is more a people problem. Overly complicated architecture, inconsistent ETL pipeline and lack of service discovery are all due to a lack of "mentality". Together with relying on consultants in the first place, I conjecture whoever in charge of your team is more a short term business metric driven type (cost, return, ROI, bonus, KPI, etc).
Thats where the challenge is