Why are they using MLRS? Are they spotting large Houthi reinforcements near border? In my opinion too late for Houthis to attempt incursion into Saudi Arabia. To be able to do that, they need operatives inside Saudi land to distract them but also need manpads/anti tank weapons/mortar cover fire to be able to get forces through the border. It needs to be organized and small in order to cause breakdown of border defense then they can bring in larger brigades .
So far Saudi Arabia is preventing every attempt to gather and has limited Houthis to small scale hit and run attacks. Either Iran and it's allies were delusional in thinking such incursion is easy or they are preparing something else. But the way it looks, Houthis and Iranian led axis have no stated objectives against Saudi Arabia. This means they lack any military strategy as the naval blockade made it very difficult for them. Most of their supporters are trying to make excuses or went back against their initial promises of liberating Najran and so on. Right now they're helpless and telling themselves that there is intense internal war amongst Saudi government. I guess that's is meant to make them feel better, lol.
So if Iranian led axis wanted to support Houthis they may need to intervene directly. Which in my opinion won't occur unless Houthis lose all their ground. So Saudi should train Yemeni forces on ground if needed and help them recapture all cities. This way we will see what Iran's reaction would be, it would get very desperate forsure.
For me this is Saudi victory. It's just that forces on ground may take time to recover all cities but nevertheless it's over. Saudi should compensate families who had civilians killed and give them spiritual support. Right now I'm curious to Iran's reaction, because this decisive victory means Iran could fear Syria is next.