There are some potential feefilter cleanups mentioned and motivated in comment https://github.com/bitcoin/bitcoin/pull/21509#issuecomment-805808485 . If you address the locking one, please be careful and make sure that `round()` is only called under a lock. See https://github.com/bitcoin/bitcoin/pull/21509#issuecomment-807992199

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if (!i2psam_arg.empty()) {
        CService addr;
        if (!Lookup(i2psam_arg, addr, 7656, fNameLookup) || !addr.IsValid()) {
            return InitError(strprintf(_("Invalid -i2psam address or hostname: '%s'"), i2psam_arg));
        }
        SetReachable(NET_I2P, true);
        SetProxy(NET_I2P, proxyType{addr});
    } else {
        SetReachable(NET_I2P, false);
    }
    connOptions.m_i2p_accept_incoming = args.GetBoolArg("-i2pacceptincoming", true);
    if (!node.connman->Start(*node.scheduler, connOptions)) {
        return false;
    }
     ***
    SetRPCWarmupFinished();
    uiInterface.InitMessage(_("Done loading").translated);
    for (const auto& client : node.chain_clients) {
        client->start(*node.scheduler);
    }
    BanMan* banman = node.banman.get();
    node.scheduler->scheduleEvery([banman]{
        banman->DumpBanlist();
    }, DUMP_BANS_INTERVAL);
#if HAVE_SYSTEM
    StartupNotify(args);
#endif
    return true;
}