Trash not existing

[Alexey]

You need to check your logs for errors, related to a filewalkers (search for walk|retain|trash and failed|error|ERROR, also for FATAL errors).
If you have any - you likely need to figure out, why your disk is so slow.
As a last resort you may disable a lazy mode:

@Alexey

Please try to disable lazy filewalker, it will turn on the normal (with a normal priority):

# run garbage collection and used-space calculation filewalkers
# as a separate subprocess with lower IO priority (default true)
pieces.enable-lazy-filewalker: false

save the config and restart the node. If you use docker, you may provide this flag after the image name: --pieces.enable-lazy-filewalker=false