Right now the limitation of one query at any time is extremely limited. When I am working on multiple PRs that may affect performance, I have to serialize draft queries that I want to run to validate them. This makes me going back and forth between multiple PRs and keep an eye on Draft completions.
It would be much more scalable with a different approach that spawns an environment per query, using cloud providers scaling capabilities. These environments can have short live span and be terminated after query is completed. Some cloud providers (AWS) support ephemeral compute as well as auto-shutdown at specified time.