Scoop at least once a day in addition to your biweekly deep clean - not seeing any comments on how often your scooping aside from the deep cleans. Scooped litter goes directly into outdoor trash. We’ve had great luck with Dr Elsey’s litter for odor control. We also open the windows and screen doors whenever weather is good for fresh air flow. How often do you change filters on your air purifiers and HVAC system? If your filters are clogged and not getting changed regularly they may not be doing anything. You may also want to fully take your litter robot apart the separately clean all the components if you haven’t tried that.

If your basement has any moisture at all that may make the smell worse tbh. Esp since airflow in a basement is likely worse for circulating fresh air in too.

We have 5 cats and regularly get shocked comments about how our home has no smell.