I have recently updated from xca 2.4 to 2.9 and the Certificates Lists felt very slow.
I have ~800 certificates from ~40 ca in my xca database
I found out that if the "Key type" or "Key size" or "common name" column is enabled in the certificates list, it makes it extremely slow and sluggish..
When I disable all three columns it feels considerably faster
I usually have the following columns enabled:
Internal name
Date
CommonName
Key name
Key type
Key size
CA
Start date
Expiry date
CRL Expiration