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
for (size_t i = 0; i < cmpctblock.BlockTxCount(); i++) {
                    if (!partialBlock.IsTxAvailable(i))
                        req.indexes.push_back(i);
                }
                if (req.indexes.empty()) {
                    
                    BlockTransactions txn;
                    txn.blockhash = cmpctblock.header.GetHash();
                    blockTxnMsg << txn;
                    fProcessBLOCKTXN = true;
                } else {
                    req.blockhash = pindex->GetBlockHash();
                    m_connman.PushMessage(&pfrom, msgMaker.Make(NetMsgType::GETBLOCKTXN, req));
                }
            } else {
                
                
                
                
                
                PartiallyDownloadedBlock tempBlock(&m_mempool);
                ReadStatus status = tempBlock.InitData(cmpctblock, vExtraTxnForCompact);
                if (status != READ_STATUS_OK) {
                    
                    return;
                }
                std::vector<CTransactionRef> dummy;
                status = tempBlock.FillBlock(*pblock, dummy);
                if (status == READ_STATUS_OK) {
                    fBlockReconstructed = true;