No, because it would require different rules for testnets, and mainnet. In the mainnet, you have "satoshis per virtual byte" model, where 1 sat/vB is the bare minimum. It works well for the network, which is already 15 years old. But not so well for a brand new network, started from scratch. And many altcoins repeat the same mistake, by picking 1 sat/vB, and starting from zero coins, and then wondering, why they are getting a different outcome, than Bitcoin in 2009.

In general, testnets should not start from scratch. There is a difference between testnet and altcoin, we should do the former, not the latter. Testnet miners should not get 50 coins per block, when mainnet miners are getting 3.125 BTC plus fees. And more conditions should be more similar to the mainnet, than they really are. However, it is, what it is. The network was deployed, and we can only stick with some existing rules, and make simple changes, because it is too late for a brand new Genesis Block, for a brand new network model, and for a brand new rules. Testnet4 will succeed or fail, but the whole skeleton is already set in stone, and won't be changed. People will rather deploy testnet5, than fix testnet4, if there will be some bigger failure.

There is a command called "invalidateblock", often combined with "reconsiderblock". Usually, it is used in a scenario of re-validating a block (so there probably should be a single command, called "herewegoagainblock" or something). But miners can also abuse those commands, for forking a chain programmatically (which is a soft-fork).

So, no new commands are needed, it is all about re-using, what is already there. But so far, Garlo Nicon passed 9950 tBTC as fees, and it was not reorged. Maybe a bigger amount can be pushed in that way, we don't know yet.

However, cheating in a lottery is a double-edged sword: the traffic in testnet4 is quite low, so miners should be interested in getting new users on the board. And also, if users will abuse the lottery, for example by winning too many times, and using full-RBF, to replace lost bets with different transactions, then miners will stop running the lottery, and start claiming the full reward again.

Basically, that kind of lottery reminds me about a game of trust: https://ncase.me/trust/

And I wonder, how many things can be tested in that way. Can a no-fork sidechain run on testnet, without being wiped by dishonest users? Can some kind of lottery be deployed, without having 100% on miners' side, and 100% on users' side, but reaching a more natural equilibrium instead? There are many things, which can be tested (and which require producing your own coinbase transaction). As long as CPU mining test coins is possible, I am trying to test things, which require mining, also because I know, that when more competition will appear, then the opportunity to test those things could vanish again.