Vault web UI - very poor performance

Folks, we have over 5500 secrets engine mounts. When attempting to use the Vault web UI, at best it takes over 2mins to load up the page containing these mounts. Depending on the client and the browser, it can just spin and time out. We are on Vault 1.14.3. Any advice much appreciated.

In the Vault UI the sys/internal/ui/mounts endpoint is called to populate the list of secrets engines.
On my largest Vault install calling sys/internal/ui/mounts with a valid token returns 4.1MB in ~685ms.

The poor performance must be whatever processing happens with the Vault UI scripts in the browser.
I don’t know where to begin investigating the UI scripts and I’m not sure anyone on these messages boards knows either.