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
nodestate->pindexBestHeaderSent = pindex ? pindex : ::ChainActive().Tip();
        m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::HEADERS, vHeaders));
        return;
    }
    if (msg_type == NetMsgType::TX) {
        
        
        
        if ((!g_relay_txes && !pfrom.HasPermission(PF_RELAY)) || (pfrom.m_tx_relay == nullptr))
        {
            LogPrint(BCLog::NET, "transaction sent in violation of protocol peer=%d\n", pfrom.GetId());
            pfrom.fDisconnect = true;
            return;
        }
        CTransactionRef ptx;
        vRecv >> ptx;
        const CTransaction& tx = *ptx;
        const uint256& txid = ptx->GetHash();
        const uint256& wtxid = ptx->GetWitnessHash();
        LOCK2(cs_main, g_cs_orphans);
        CNodeState* nodestate = State(pfrom.GetId());
        const uint256& hash = nodestate->m_wtxid_relay ? wtxid : txid;
        pfrom.AddKnownTx(hash);
        if (nodestate->m_wtxid_relay && txid != wtxid) {