One part I am still confused about is how the new covenant script rules (bip119 op_ctv) get reinforced. Is it the wallet devs that write the rules in their wallet? So user could just use another wallet as my reply above. Or are the rules (whitelisting/blacklisting for example)  reinforced by miners on chain & they simply reject all /whitelisted/blacklisted accounts from the block.

Upper layers are permissionless so additional requirements can be added. Wallets & exchanges can be considered l2. So if wallet providers decide to blacklist, KYC, comply with regulators and so on its their right. Users rights is to chose which wallet to use according to their need & principles.

Onchain l1 that's where I am extremely worried. If miners get to reinforce on l1 that means all wallets & everything built on top of l1 such as l2, l3 etc need to follow the same rules then that's literally hell for onchain neutrality and fungibility.

Onchain l1 needs to stay censorship resistant and neutral.

Can any one clarify this?