We all make choices with tanks and you've gone without surface floating plants and you removed a fast growing stem plant, and you are using EI, though I note on lower dosage now. With soil I don't think most tanks don't need water column macro nutrients for weeks if not months. I prefer soil under sand to reduce the high water column nutrition it creates especially in the early stages. And from what I can see of your pH indicator you are probably a bit CO2 low, but to make that call you need to know your KH and of course the indicator is always showing the pH as it was 2 or 3 hours ago.
Floating plants help in so many ways. I also plant more of the substrate than you did, with cheap fast growing plants.
I approve thoroughly of some aeration during the dark period to reduce the risk to fish, 5 hours seems a bit much and I think, you may, I can't be sure, losing a considerable amount of the CO2 you have injected in. A couple of hours from one air stone for two hours towards the end of the dark stage, seems to be enough to ensure no gasping fish in most even medium sized tanks. In fact I have run several tanks with 24 hour low bubble count CO2 without fish distress, losses and no aeration. But in the summer especially, some night time aeration is almost certainly a good idea. Some bigger fish of course are more vulnerable, for harlequins and gourami fish both are pretty tolerant in terms of moderate O2 levels and CO2 levels around 20 ppm.
I'd also try a 6 hour photo period for a week. Then 7 hours and aim to work towards 8 hours. But above all, I personally would use hornwort, Indian fern and frogbit to cushion the tank during the initial stages and give you a visual guide to any deficiencies, the so-called duckweed index. I still use floating plants on a system in its 7th year. But I use very high light and a lot of CO2 and lean dosing. That is my choice of course and my tank is definitely not to everybody's taste I'll load a photo, it should give you something to at least think about, and I promise you my tank is not algae free, but the plants are healthy and the algae is quite minimal.
Good luck.