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
if (recentRejects->contains(parent_txid)) {
                    fRejectedParents = true;
                    break;
                }
            }
            if (!fRejectedParents) {
                const auto current_time = GetTime<std::chrono::microseconds>();
                for (const uint256& parent_txid : unique_parents) {
                    
                    
                    
                    
                    
                    const GenTxid gtxid{false, parent_txid};
                    pfrom.AddKnownTx(parent_txid);
                    if (!AlreadyHaveTx(gtxid, m_mempool)) RequestTx(State(pfrom.GetId()), gtxid, current_time);
                }
                AddOrphanTx(ptx, pfrom.GetId());
                
                unsigned int nMaxOrphanTx = (unsigned int)std::max((int64_t)0, gArgs.GetArg("-maxorphantx", DEFAULT_MAX_ORPHAN_TRANSACTIONS));
                unsigned int nEvicted = LimitOrphanTxSize(nMaxOrphanTx);
                if (nEvicted > 0) {
                    LogPrint(BCLog::MEMPOOL, "mapOrphan overflow, removed %u tx\n", nEvicted);
                }
            } else {
                LogPrint(BCLog::MEMPOOL, "not keeping orphan with rejected parents %s\n",tx.GetHash().ToString());