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
bool fPeerWantsWitness = State(pfrom.GetId())->fWantsCmpctWitness;
                int nSendFlags = fPeerWantsWitness ? 0 : SERIALIZE_TRANSACTION_NO_WITNESS;
                if (CanDirectFetch(consensusParams) && pindex->nHeight >= ::ChainActive().Height() - MAX_CMPCTBLOCK_DEPTH) {
                    if ((fPeerWantsWitness || !fWitnessesPresentInARecentCompactBlock) && a_recent_compact_block && a_recent_compact_block->header.GetHash() == pindex->GetBlockHash()) {
                        connman.PushMessage(&pfrom, msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK, *a_recent_compact_block));
                    } else {
                        CBlockHeaderAndShortTxIDs cmpctblock(*pblock, fPeerWantsWitness);
                        connman.PushMessage(&pfrom, msgMaker.Make(nSendFlags, NetMsgType::CMPCTBLOCK, cmpctblock));
                    }
                } else {
                    connman.PushMessage(&pfrom, msgMaker.Make(nSendFlags, NetMsgType::BLOCK, *pblock));
                }
            }
        }
        
        if (inv.hash == pfrom.hashContinue)
        {
            
            
            
            std::vector<CInv> vInv;
            vInv.push_back(CInv(MSG_BLOCK, ::ChainActive().Tip()->GetBlockHash()));
            connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::INV, vInv));
            pfrom.hashContinue.SetNull();
        }
    }
}
static CTransactionRef FindTxForGetData(const CTxMemPool& mempool, const CNode& peer, const GenTxid& gtxid, const std::chrono::seconds mempool_req, const std::chrono::seconds now) LOCKS_EXCLUDED(cs_main)