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
MarkBlockAsInFlight(m_mempool, pfrom.GetId(), pindex->GetBlockHash(), pindex);
                    LogPrint(BCLog::NET, "Requesting block %s from  peer=%d\n",
                            pindex->GetBlockHash().ToString(), pfrom.GetId());
                }
                if (vGetData.size() > 1) {
                    LogPrint(BCLog::NET, "Downloading blocks toward %s (%d) via headers direct fetch\n",
                            pindexLast->GetBlockHash().ToString(), pindexLast->nHeight);
                }
                if (vGetData.size() > 0) {
                    if (nodestate->fSupportsDesiredCmpctVersion && vGetData.size() == 1 && mapBlocksInFlight.size() == 1 && pindexLast->pprev->IsValid(BLOCK_VALID_CHAIN)) {
                        
                        vGetData[0] = CInv(MSG_CMPCT_BLOCK, vGetData[0].hash);
                    }
                    m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::GETDATA, vGetData));
                }
            }
        }
        
        
        if (::ChainstateActive().IsInitialBlockDownload() && nCount != MAX_HEADERS_RESULTS) {
            
            
            if (nodestate->pindexBestKnownBlock && nodestate->pindexBestKnownBlock->nChainWork < nMinimumChainWork) {