Help! Peppers ain't doing sh*t

Hello! I posted before that my peppers weren't doing sht and some kind soul pointed to my temperature as the issue, so I moved the tray to a warmer spot and put it back on the heat mat and for some reason my peppers still ain't doin sht!

Details: -Planted on 1/17 in ocean forest potting soil -Have them under a grow light. Lux reading was around 5000 -In the cooler room, temps were 64-68 F. Now for the past two weeks, a thermometer next to the tray reads ~70-75 F - I water when the soil is dry

Some have started putting on first real leaves but they've remained tiny for weeks, barely growing if at all. I'm trying so hard and am at a loss here! Anyone have any insight on why they are so stunted?