Mining Theory – What incentives should there be for miners not to lie about how long it takes to mine a block?

What incentivizes miners (all miners, regardless of hash rate) to disagree with each other on including real-time in blocks and times such as the 10 minutes it takes to produce a block? What I mean is, if we assume all miners together need 10 minutes, the probability ratio of “finding the correct block and distributing the reward” doesn’t change (we just lower the required threshold). In this case, miners will mine a block in less than 2/3/4 minutes on average (I put in an arbitrary number), and set the time on the timestamp as if they need 10 minutes (of course, all miners will have +2h To comply with the rules, you must wait before sending a block. I can only see good things about them here. Because using this method, every miner will spend much less electricity finding a single block, which can lead to huge profits.

So what is the incentive for miners not to lie about how long it takes to mine a block? and to reject such agreements.?