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
LOCK(pto->m_tx_relay->cs_filter);
                    while (!vInvTx.empty() && nRelayedTransactions < INVENTORY_BROADCAST_MAX) {
                        
                        std::pop_heap(vInvTx.begin(), vInvTx.end(), compareInvMempoolOrder);
                        std::set<uint256>::iterator it = vInvTx.back();
                        vInvTx.pop_back();
                        uint256 hash = *it;
                        CInv inv(state.m_wtxid_relay ? MSG_WTX : MSG_TX, hash);
                        
                        pto->m_tx_relay->setInventoryTxToSend.erase(it);
                        
                        if (pto->m_tx_relay->filterInventoryKnown.contains(hash)) {
                            continue;
                        }
                        
                        auto txinfo = m_mempool.info(ToGenTxid(inv));
                        if (!txinfo.tx) {
                            continue;
                        }
                        auto txid = txinfo.tx->GetHash();
                        auto wtxid = txinfo.tx->GetWitnessHash();
                        
                        if (txinfo.fee < filterrate.GetFee(txinfo.vsize)) {
                            continue;
                        }
                        if (pto->m_tx_relay->pfilter && !pto->m_tx_relay->pfilter->IsRelevantAndUpdate(*txinfo.tx)) continue;
                        
                        State(pto->GetId())->m_recently_announced_invs.insert(hash);
                        vInv.push_back(inv);
                        nRelayedTransactions++;