I also think L2 layers are not genuinely a Bitcoin network but the issuer's token's network. Since Bitcoin programmability is limited I do not think that it can support advanced smart contracts unless it is done outside the natural layer of Bitcoin. But as long as these L2 layers are not as intrusive as BRC-20 that affect the Bitcoin network congestion, I do not mind them developing this kind of smart contract because it enhances the applicability of Bitcoin to real-life case use.
The Bitcoin network does not support advanced smart contracts, or more advanced than it already has. Separate networks do support them, but they do not use bitcoin as currency. Sidechains, specifically, such as Stacks or Rootstock, while they do make use of the Proof-of-Work being done on the Layer 1, they mint their own tokens, which should be viewed more as altcoins than Bitcoin, IMO.
I agree, anything outside the Bitcoin network that issues a coin or token is an altcoin.