AFAICT, as of commit a0a422c,  we have 2 different logics to evict outbound peers : lagging-chain (`ConsiderEviction`) and (`CheckForStaleTipAndEvictPeers`). The former to sanitize out lazy/buggy peers who have never sent us a valid header and are always staying behind our tip, the latter triggered in case of stale tip due to block variance to seek a better chain by rotating our outbound peers if we already reach an outbound limit (`EvictExtraOutboundPeers`).

Block-relay-only peers were introduced by #15719. Contrary to outbound full-relay peers who provided us at least a useful header, they're not protected by lagging-chain eviction.

We actually have a comment inside `ProcessHeadersMessage` indicating the contrary behavior. We should either document cleanly that block-relay-only aren't protected or effectively extend the scope of protection to them.

Hinted during #19724 review, see https://github.com/bitcoin/bitcoin/pull/19724#discussion_r475144532
{
    return LookupBlockIndex(block_hash) != nullptr;
}
void RelayTransaction(const uint256& txid, const uint256& wtxid, const CConnman& connman)
{
    connman.ForEachNode([&txid, &wtxid](CNode* pnode) EXCLUSIVE_LOCKS_REQUIRED(::cs_main) {
        AssertLockHeld(::cs_main);
        CNodeState* state = State(pnode->GetId());
        if (state == nullptr) return;
        if (state->m_wtxid_relay) {
            pnode->PushTxInventory(wtxid);
        } else {
            pnode->PushTxInventory(txid);
        }
    });
}
static void RelayAddress(const CAddress& addr, bool fReachable, const CConnman& connman)