Have you tried deleting robot account from under manage access or simply unallocated from the folder?
On community edition, only 1 production and 1 testing bot is allocated. So, you can’t create more bots, When you try it will show the error like Quota reached, cannot create more objects.
Check the number of bots in Orchestrator, follow the below steps,
→ Login to orchestrator, Go to Tenant → Licenses Tab → There you can find the number of robots.
Can you share that screenshot with us?
If you are still not able to create robots even after deleting all its references, you can consider deleting your organization from under admin-> settings and then recreate the new one.