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
uint32_t nFetchFlags = 0;
    if ((pfrom.GetLocalServices() & NODE_WITNESS) && State(pfrom.GetId())->fHaveWitness) {
        nFetchFlags |= MSG_WITNESS_FLAG;
    }
    return nFetchFlags;
}
void PeerManager::SendBlockTransactions(CNode& pfrom, const CBlock& block, const BlockTransactionsRequest& req) {
    BlockTransactions resp(req);
    for (size_t i = 0; i < req.indexes.size(); i++) {
        if (req.indexes[i] >= block.vtx.size()) {
            Misbehaving(pfrom.GetId(), 100, "getblocktxn with out-of-bounds tx indices");
            return;
        }
        resp.txn[i] = block.vtx[req.indexes[i]];
    }
    LOCK(cs_main);
    const CNetMsgMaker msgMaker(pfrom.GetCommonVersion());
    int nSendFlags = State(pfrom.GetId())->fWantsCmpctWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS;
    m_connman.PushMessage(&pfrom, msgMaker.Make(nSendFlags, NetMsgType::BLOCKTXN, resp));
}
void PeerManager::ProcessHeadersMessage(CNode& pfrom, const std::vector<CBlockHeader>& headers, bool via_compact_block)