Redesign your network so you can use PCQ.
Scaling to 4,000 simple queues is ridiculous. Feasible, maybe, but the administrative overhead is no worse than a network redesign and doing things right in the first place .
Specific answers require specific questions. When in doubt, post the output of "/ip address print detail", "/ip route print detail", "/interface print detail", "/ip firewall export", and an accurate network diagram.