Modern Linux systems use the powerful systemd framework for process-initialization, logging, and more. The logging facility is called the journal and is accessed via the journalctl(1) utility. We use it to verify that it's indeed the SELinux LSM that has caused the issue:

$ journalctl --boot | grep memprot
[...]
<timestamp> <host> python3[31861]: SELinux is preventing memprot from using the execheap access on a process.
 If you do not think memprot should need to map heap memory that is both writable and executable.
 If you believe that memprot should be allowed execheap access on processes labeled unconfined_t by default.
 # ausearch -c 'memprot' --raw | audit2allow -M my-memprot
 # semodule -X 300 -i my-memprot.pp

It even shows us exactly how we can allow the access.