This is a known issue that I've been working on. The wallet is a large module in Bitcoin Core and changing it takes quite a bit of time.

On 08/20/2022 10:16 AM, Felipe Micaroni Lalli via bitcoin-dev wrote:

> 8.1) Can we "optimize" a huge wallet without moving the funds to a new one? Like a "fsck" or eqv?

You can remove old transactions using the removeprunedfunds RPC. That should greatly speed up balance calculations and transaction creation.

> 8.2) Can we improve the cache usage somehow? Putting the entire wallet in memory, for example?

It's already entirely in memory.