Transitioning from a C1 OLED to a standard LCD monitor is a big jump in contrast quality, so you might want to consider managing your expectations regarding black levels. Most displays under $600 use IPS panels which are great for motion but basically struggle with HDR compared to your old TV. I would suggest looking into these specific models that fit your budget and timeline:

• LG 27GR93U-B 27-inch 4K 144Hz HDMI 2.1
• Gigabyte M27U 27-inch 4K 160Hz
• Sony INZONE M9 27-inch 4K 144Hz HDR600 Be careful with the Gigabyte if you care about HDR because its pretty weak on that front. The Sony is likely your best bet for better contrast since it has actual local dimming, tho it might be pushing your $600 limit depending on where you shop. Just make sure to update the firmware right away to avoid VRR issues or flickering that some users reported early on.

Coming back to this after seeing your budget... honestly, moving from a C1 to a standard monitor is gonna be a culture shock for your eyes. I have been through a dozen panels over the last few years and nothing hits quite like OLED contrast, but with a $600 cap, you can get pretty close if you hunt for Mini-LED. Since you are on a deadline, here are a few that dont totally suck for a PS5 setup:

• The Sony INZONE M9 27 inch 4K HDR 144Hz is basically built for your console. It uses full-array local dimming which helps keep those blacks actually black instead of that muddy grey you see on cheap screens. It handles HDR way better than most mid-range stuff I've tried.
• If you want something super reliable, check the LG 27GR93U-B 27 inch UHD 144Hz. Its a fast IPS panel. Ngl, the contrast wont touch your C1, but the motion clarity is insane and it has full HDMI 2.1 support so VRR works flawlessly.
• If you can find it in stock, the Cooler Master Tempest GP27U 27 inch Mini-LED 4K is a sleeper hit. The HDR peak brightness is actually wild for the price point. Just a heads up, since you're in a tiny studio, you might notice IPS glow more if you play in the dark at night. Tbh, if you can find a sale, a 27 inch OLED would be the dream, but for $600 that Sony is probably your best bet by Tuesday.

TLDR: Check the RTINGS comparison tool. Just found this thread and honestly I went through this same stress when I moved. Basically you should just search ps5 monitor spreadsheet on reddit. Theres a guy on youtube who does technical deep-dives into eotf tracking and vrr flicker for every panel under 600... his 2024 guide is the bible for this. Its way easier than guessing and you wont waste money, tbh.