Lump Sum or DCA during High Valuations

Hey guys, looking for a sanity check on my math and my mindset. We’re currently sitting on about $1M in the market, so we’re already "in the game." However, we’ve got a chunk of cash sitting on the sidelines, and I’m having a really hard time pulling the trigger on a lump sum into the market with the Shiller PE hovering around 40x. Historically, buying at these valuations feels like asking for a lost decade. Here’s the alternative I’m looking at: Instead of dumping the cash into VTI/VOO today, we could just pay off our rental property. If we kill that debt, it frees up enough cash flow to where we’d be able to put $6k net into the market every single month. The logic: If the market trades sideways or hits a "lost decade": This wins big. I’ve run the numbers, and the "Debt Payoff + $6k/mo DCA" strategy performs almost double what a lump sum would do in a flat market. If the market keeps ripping: We basically break even or trail slightly, but we’re doing it with way less stress and a paid-off asset. It feels like I’m creating a "buying machine" that lets me sleep better at night if the bubble finally pops, without totally missing out if things keep going up. Am I overthinking the 40x Shiller PE? Or does de-risking the real estate to fund a massive monthly DCA actually make sense at these levels? Curious to hear from anyone else who is feeling "valuation vertigo" despite having a solid portfolio already.