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
static constexpr std::chrono::seconds RELAY_TX_CACHE_TIME = std::chrono::minutes{15};
static constexpr std::chrono::seconds UNCONDITIONAL_RELAY_DELAY = std::chrono::minutes{2};
/** Headers download timeout expressed in microseconds
 *  Timeout = base + per_header * (expected number of headers) */
static constexpr int64_t HEADERS_DOWNLOAD_TIMEOUT_BASE = 15 * 60 * 1000000; 
static constexpr int64_t HEADERS_DOWNLOAD_TIMEOUT_PER_HEADER = 1000; 
/** Protect at least this many outbound peers from disconnection due to slow/
 * behind headers chain.
 */
static constexpr int32_t MAX_OUTBOUND_PEERS_TO_PROTECT_FROM_DISCONNECT = 4;
static constexpr int64_t CHAIN_SYNC_TIMEOUT = 20 * 60; 
static constexpr int64_t STALE_CHECK_INTERVAL = 10 * 60; 
static constexpr int64_t EXTRA_PEER_CHECK_INTERVAL = 45;
static constexpr int64_t MINIMUM_CONNECT_TIME = 30;
static constexpr uint64_t RANDOMIZER_ID_ADDRESS_RELAY = 0x3cac0035b5866b90ULL;
static constexpr int STALE_RELAY_AGE_LIMIT = 30 * 24 * 60 * 60;
static constexpr int HISTORICAL_BLOCK_AGE = 7 * 24 * 60 * 60;
static constexpr std::chrono::minutes PING_INTERVAL{2};
static const unsigned int MAX_LOCATOR_SZ = 101;
static const unsigned int MAX_INV_SZ = 50000;
static constexpr int32_t MAX_PEER_TX_IN_FLIGHT = 100;
static constexpr int32_t MAX_PEER_TX_ANNOUNCEMENTS = 2 * MAX_INV_SZ;
static constexpr std::chrono::microseconds TXID_RELAY_DELAY{std::chrono::seconds{2}};
static constexpr std::chrono::microseconds INBOUND_PEER_TX_DELAY{std::chrono::seconds{2}};
static constexpr std::chrono::microseconds GETDATA_TX_INTERVAL{std::chrono::seconds{60}};
static constexpr std::chrono::microseconds MAX_GETDATA_RANDOM_DELAY{std::chrono::seconds{2}};
static constexpr std::chrono::microseconds TX_EXPIRY_INTERVAL{GETDATA_TX_INTERVAL * 10};
static_assert(INBOUND_PEER_TX_DELAY >= MAX_GETDATA_RANDOM_DELAY,
"To preserve security, MAX_GETDATA_RANDOM_DELAY should not exceed INBOUND_PEER_DELAY");
static const unsigned int MAX_GETDATA_SZ = 1000;