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 const int MAX_BLOCKS_IN_TRANSIT_PER_PEER = 16;
static const unsigned int BLOCK_STALLING_TIMEOUT = 2;
/** Number of headers sent in one getheaders result. We rely on the assumption that if a peer sends
 *  less than this number, we reached its tip. Changing this value is a protocol upgrade. */
static const unsigned int MAX_HEADERS_RESULTS = 2000;
/** Maximum depth of blocks we're willing to serve as compact blocks to peers
 *  when requested. For older blocks, a regular BLOCK response will be sent. */
static const int MAX_CMPCTBLOCK_DEPTH = 5;
static const int MAX_BLOCKTXN_DEPTH = 10;
/** Size of the "block download window": how far ahead of our current height do we fetch?
 *  Larger windows tolerate larger download speed differences between peer, but increase the potential
 *  degree of disordering of blocks on disk (which make reindexing and pruning harder). We'll probably
 *  want to make this a per-peer adaptive value at some point. */
static const unsigned int BLOCK_DOWNLOAD_WINDOW = 1024;
static const int64_t BLOCK_DOWNLOAD_TIMEOUT_BASE = 1000000;
static const int64_t BLOCK_DOWNLOAD_TIMEOUT_PER_PEER = 500000;
static const unsigned int MAX_BLOCKS_TO_ANNOUNCE = 8;
static const int MAX_UNCONNECTING_HEADERS = 10;
static const unsigned int NODE_NETWORK_LIMITED_MIN_BLOCKS = 288;
static constexpr std::chrono::hours AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL{24};
static constexpr std::chrono::seconds AVG_ADDRESS_BROADCAST_INTERVAL{30};
/** Average delay between trickled inventory transmissions in seconds.
 *  Blocks and peers with noban permission bypass this, outbound peers get half this delay. */
static const unsigned int INVENTORY_BROADCAST_INTERVAL = 5;
/** Maximum rate of inventory items to send per second.
 *  Limits the impact of low-fee transaction floods. */
static constexpr unsigned int INVENTORY_BROADCAST_PER_SECOND = 7;
static constexpr unsigned int INVENTORY_BROADCAST_MAX = INVENTORY_BROADCAST_PER_SECOND * INVENTORY_BROADCAST_INTERVAL;
static constexpr unsigned int INVENTORY_MAX_RECENT_RELAY = 3500;
/** Verify that INVENTORY_MAX_RECENT_RELAY is enough to cache everything typically