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
connman.PushMessage(&peer, std::move(msg));
}
void PeerManager::ProcessMessage(CNode& pfrom, const std::string& msg_type, CDataStream& vRecv,
                                         const std::chrono::microseconds time_received,
                                         const std::atomic<bool>& interruptMsgProc)
{
    LogPrint(BCLog::NET, "received: %s (%u bytes) peer=%d\n", SanitizeString(msg_type), vRecv.size(), pfrom.GetId());
    if (gArgs.IsArgSet("-dropmessagestest") && GetRand(gArgs.GetArg("-dropmessagestest", 0)) == 0)
    {
        LogPrintf("dropmessagestest DROPPING RECV MESSAGE\n");
        return;
    }
    if (msg_type == NetMsgType::VERSION) {
        
        if (pfrom.nVersion != 0)
        {
            Misbehaving(pfrom.GetId(), 1, "redundant version message");
            return;
        }
        int64_t nTime;
        CAddress addrMe;
        CAddress addrFrom;
        uint64_t nNonce = 1;
        uint64_t nServiceInt;
        ServiceFlags nServices;
        int nVersion;
        std::string cleanSubVer;
        int nStartingHeight = -1;
        bool fRelay = true;
        vRecv >> nVersion >> nServiceInt >> nTime >> addrMe;