The problem here is normalization of deviance across the entire organization. That has nothing to do with tasks.
The task #0 is sit down with the team and ask them to say in their own words what do they think about the project, about their engineering good practices, etc. See how aware are they about the problem they have created.
Try to understand how the status quo became normal and acceptable, before the same thing happens to you.
If this shit happened in the first place was because likely everyone was too busy living in their Jira alternate reality where you benefit from the perverse incentives made possible by the lack of visibility on code quality.
The task #0 is sit down with the team and ask them to say in their own words what do they think about the project, about their engineering good practices, etc. See how aware are they about the problem they have created.
Try to understand how the status quo became normal and acceptable, before the same thing happens to you.
If this shit happened in the first place was because likely everyone was too busy living in their Jira alternate reality where you benefit from the perverse incentives made possible by the lack of visibility on code quality.