I asked Grok what it would do differently if rebuilding Bitcoin from scratch.

I'd keep the core design: proof of work, a fixed supply and a scripting language that's simple to check. I'd change the parts that caused years of fighting or have to be bolted on now:

Make the protocol unchangeable at launch. Freeze the rules and the opcodes from day one, with block size limits left to miners and the market, so there's no room for scaling wars or forks over policy.
Get rid of transaction malleability. Exclude signatures from the txid from the start, so payment channels and chains of unconfirmed transactions are safe without a SegWit-style patch.
Prove payments directly between the two parties. Make SPV and payer-to-payee exchange part of the standard, with proofs travelling alongside each payment, so ordinary users never need a full node or a broadcast lottery. That's basically what BRC-100 and BEEF bolt on today.
Plan for fees replacing the block reward. Halving the reward every four years leaves miner revenue a guessing game. I'd design so lots of tiny-fee transactions are expected to pay for security, rather than hoping that happens.
Keep miners honest about what they include. Have them commit to a canonical transaction order, which helps block propagation and makes it harder to quietly censor transactions.
Plan an upgrade path for signatures. Leave room to switch to a post-quantum signature scheme someday, without a fork that leaves old coins exposed.
Name identity and keys up front. Start with a standard for linking keys to identity, along with key derivation and recovery, instead of leaving it to wallets.
Much of that list is the BSV thesis: a fixed protocol, big blocks and peer-to-peer SPV. Your stack is already betting on it, and micropayments like Fuse's 500-sat calls are the fee-driven security future made concrete.