In-memory OLTP databases take very long to recover during startup

we use SQL Server 2019 on Windows with in-memory oltp activated on some databases. After a server reboot/service restart, the in-memory databases take very long to be available (more than an hour) even though most tables are not durable. The size of memory optimized objects is very small: 10 MB We see a background session on master db with wait type (110514580ms)WAIT_XTP_RECOVERY and almost no reads. CPU cores are at 100%. Disks are idling. We use transparent data encryption (TDE) for this database. This database uses synonyms to access another db on the same instance. It uses service broker. Instance has transactional replication set-up on databases without in-memory activated. Adding CPU makes it faster. This is a lowend machine, but not crap. XTP engine 2.11. Any idea what's going on?