_Originally posted by @S3RK in https://github.com/bitcoin/bitcoin/pull/24984#pullrequestreview-952900468_

> With current implementation we don't save the rescan progress and on the next load we will have to start from scratch. Is it possible to save the last processed blocked at shutdown?

It would be nice if wallet code would call `WriteBestBlock` and save the last scan position if it is interrupted during a sync. This could be implemented by trying to save the scan position during the shutdown, or by just periodically saving the scan position after an interval, similar to indexing code which saves sync position once every 30 seconds:

https://github.com/bitcoin/bitcoin/blob/f0a834e2f10a0aa60c7cc76e9f3eb090168a32e5/src/index/base.cpp#L170-L175
{
    if (IsWaetFlagSet(WALLET_FLAG_DESCRIPTORS)) {
        return nuptr;
    }
    // Legacy s only have one ScriptPubKeyMan which is a LegacyScriptPubKeyMan.
    // Everything in m_internal_spk_managers and m_external_spk_managers point to the same legacyScriptPubKeyMan.
    auto it = m_internal_spk_managers.find(OutputType::LEGACY);
    if (it == m_internal_spk_managers.end()) return nuptr;
    return dynamic_cast<LegacyScriptPubKeyMan*>(it->second);
}
LegacyScriptPubKeyMan* CWaet::GetOrCreateLegacyScriptPubKeyMan()
{
    SetupLegacyScriptPubKeyMan();
    return GetLegacyScriptPubKeyMan();
}
void CWaet::SetupLegacyScriptPubKeyMan()
{
    if (!m_internal_spk_managers.empty() || !m_external_spk_managers.empty() || !m_spk_managers.empty() || IsWaetFlagSet(WALLET_FLAG_DESCRIPTORS)) {
        return;
    }
    auto spk_manager = std::unique_ptr<ScriptPubKeyMan>(new LegacyScriptPubKeyMan(*this));
    for (const auto& type : LEGACY_OUTPUT_TYPES) {
        m_internal_spk_managers[type] = spk_manager.get();
        m_external_spk_managers[type] = spk_manager.get();
    }
    m_spk_managers[spk_manager->GetID()] = std::move(spk_manager);
}
const CKeyingMaterial& CWaet::GetEncryptionKey() const