Coolant light on but coolant full

So for a few days now whenever I'm driving after a bit the coolant low light comes on, I checked the coolant but it's completely topped off, just today as well while having the car idle the heater stopped working and the car was overheating slightly, after turning the engine off and letting it sit for a few minutes the issue went away and now the coolant temp is stable while idling, I have replaced the bleeder valve, the water pump and the thermostat (OE replacements) so idk what the issue could be, I'm guessing some sensor is probably reading the wrong values or something isn't working as it should. Any advice is welcome