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
CBlock block;
        bool ret = ReadBlockFromDisk(block, pindex, m_chainparams.GetConsensus());
        assert(ret);
        SendBlockTransactions(pfrom, block, req);
        return;
    }
    if (msg_type == NetMsgType::GETHEADERS) {
        CBlockLocator locator;
        uint256 hashStop;
        vRecv >> locator >> hashStop;
        if (locator.vHave.size() > MAX_LOCATOR_SZ) {
            LogPrint(BCLog::NET, "getheaders locator size %lld > %d, disconnect peer=%d\n", locator.vHave.size(), MAX_LOCATOR_SZ, pfrom.GetId());
            pfrom.fDisconnect = true;
            return;
        }
        LOCK(cs_main);
        if (::ChainstateActive().IsInitialBlockDownload() && !pfrom.HasPermission(PF_DOWNLOAD)) {
            LogPrint(BCLog::NET, "Ignoring getheaders from peer=%d because node is in initial block download\n", pfrom.GetId());
            return;
        }
        CNodeState *nodestate = State(pfrom.GetId());
        const CBlockIndex* pindex = nullptr;
        if (locator.IsNull())
        {
            
            pindex = LookupBlockIndex(hashStop);
            if (!pindex) {
                return;
            }
            if (!BlockRequestAllowed(pindex, m_chainparams.GetConsensus())) {