[finnthehuman]

Process process process.

Start with researching formal "quality management systems." At the very least that'll introduce you to using FMEAs, external standards, rigorous design reviews and testing, quality gates between development and production (if they're not a PITA, they're not working) and traceability for everything in production.

There are off-the-shelf learning materials for all of it.

If you do go down that road hire someone with QMS experience to design your process and handhold your team through the transition. Otherwise you're likely to over-complicate it for a less effective result.