Isn't 84 bytes allowed by BIP-110?
No, 83 is allowed, everything above it is not.
P2PK isn't that deprecated or considered unsafe by now?
If you think it is unsafe, then go on, and move thousands of BTCs, sitting now on P2PK, into your address. Early miners put them 50 BTC per public key, so go on, there is a lot of incentive, if you think it can be broken.
Yes, it is "deprecated", but you can still use it, if you want. For example:
https://mempool.space/tx/909b486928dc415d9b6613fcc70ccdbfb4d2f88516a040522365b95794774608BIP-110 supporters often said, that no payments are affected. Which means, that they probably consider P2PK to be "not a payment", or "a spam", even though it works, it is used since 2009, and Satoshi used it in the first transactions. Which is why using P2PK is a nice way to troll them, because it pushes less on-chain bytes, than for example P2PKH, and at the same time, this less spammy method is blocked by BIP-110 for absolutely no reason (because P2PK for compressed and uncompressed keys is always smaller than 83 bytes, allowed in OP_RETURN; it is funny to use less bytes than OP_RETURN allows, and still be blocked by them).
I think this whole thing started with SegWit anyway.
Yes, of course. The same things can be pushed through 15-of-15 multisigs inside P2SH. What then?
Im not going to be doing anything different because of Luke's fork.
Your coins, your choice. If you don't care, then your transactions could be just replayed in both networks.
How do I check if the coins I own are already splitted anyway?
If you copy-paste your transaction to another network, and it will be broadcasted, then your coins are not splitted.
what block explorer will show this?
non-BIP-110:
https://mempool.space/BIP-110:
https://mempool.guide/
