light power

ATTENTION! Your temperature probe is placed the wrong place, which gives you higher temperature readings and lower RH readings than you actually have at the plants' canopy, which is where it matters - The probe must be around the plants' canopy to get suable readings You can easily crank it to max, I run 400w in the same size tent :)

I had a quick scan of your diary and one picture shows your extractor fan pumping into the room the tent is in, by adding ducting to the end you could move the air to a different room and that will help lower temps in the room which will lower temps in the tent.

low power, low light

Should try to give 35-40DLI... Efficacy varies, so watts is an inaccurate way to gauge this. If heat or RH is an issue while doing that, do your best. 28-29C isn't too hot, but 29c / 45% is 2.2 kPa. This will eventually cause problems. If there is no option to increase RH, then yes, you want fewer watts to avoid extremely high VPD. Humidifiers are cheap. Heating/cooling/dehumidification is expensive. When you get temp and rh clicking together, the plant can handle more light, too.

Also the temp display is where the sensor should be not at the top of the tent. I agree.. if you can remove the filter you will be in the green

You are using a carbon filter on the exhaust, this will increase resistance 50% on intake, means you need to double the size. Otherwise your exhaust will not be able to remove heat faster than it accumulates. Should not be such a temp spike from 100w. More a throughout bottlenecked preventing efficient air exchange. Fix that and tent drops 5-6 degrees.