P2Pool is a sidechain to Monero, and P2Pool blocks are potentially Monero blocks. Each miner submits block templates that include payouts to all of the miners that are mining at the same time (those that currently have shares in the PPLNS window). High quality block templates are added to the P2Pool blockchain as blocks; these count as "shares" for the miner who found them.
P2Pool is a clever new way of mining Monero, which allows miners to receive the frequent payouts offered by pools without needing to trust a centralized pool. P2Pool is a Peer-To-Peer mining pool that gives miners full control over their Monero node and what it mines. More details in <a href="/2021/10/05/p2pool-released.html">the announcement post</a>.
The Monero Research Lab released an annotated version of the cryptonote whitepaper. This is sort of like an informal review of the claims that are made line-by-line of the whitepaper. It also explains some of the harder concepts in relatively easy to understand terms.
The CLI wallet gives you the total control over your Monero node and funds. Highly customizable and includes various analysis tools, as well as an HTTP RPC and 0MQ interface.
The problem is that these devices are very expensive and can be afforded by few. This leads to few entities owning a big amount of the hashrate of the network, which is a serious threat to the security of the network itself. For example, if big ASIC operators collude and manage to gain the majority of the hashrate of the network, they could arbitrarily reject transactions.
The problem is being discussed and solutions are being elaborated. In the meantime, if you get a warning from your antivirus, make sure the software you downloaded is legitimate (see the guides linked below), then add an exception for it in your antivirus, so that it won't get removed or blocked. If you need assistance, feel free to contact the community.