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
pfrom.AddKnownTx(txid);
        }
        TxValidationState state;
        for (const GenTxid& gtxid : {GenTxid(false, txid), GenTxid(true, wtxid)}) {
            nodestate->m_tx_download.m_tx_announced.erase(gtxid.GetHash());
            nodestate->m_tx_download.m_tx_in_flight.erase(gtxid.GetHash());
            EraseTxRequest(gtxid);
        }
        std::list<CTransactionRef> lRemovedTxn;
        
        
        
        
        
        
        
        
        
        
        
        
        if (!AlreadyHaveTx(GenTxid(true, wtxid), m_mempool) &&
            AcceptToMemoryPool(m_mempool, state, ptx, &lRemovedTxn, false , 0 )) {
            m_mempool.check(&::ChainstateActive().CoinsTip());
            RelayTransaction(tx.GetHash(), tx.GetWitnessHash(), m_connman);
            for (unsigned int i = 0; i < tx.vout.size(); i++) {
                auto it_by_prev = mapOrphanTransactionsByPrev.find(COutPoint(txid, i));
                if (it_by_prev != mapOrphanTransactionsByPrev.end()) {