This is what I would do if you have moderate-high lighting, rich co2, and fast growing stems.
1. Follow the water change schedule to a T
2. Get your CO2 correct and stable, make sure your flow in the tank is good.
2. Ditch the thrive and buy a 1lb bag of KNO3, KH2P04, K2S04, and a commercial trace mix like seachem flourish
3. The bag of KNO3 is going to sit on the side for a couple months, This is why the thrive is no good because it will add N along with the other things you need. You don't need any N right now. Daily you are going to add 5ppm KH2PO4, and the trace mix. aquasoil absorbs alot of P, if you have a powersand layer it will absorb even more. I've been adding 5ppm P per day for 4 months and if I test right now it will read 2ppm. At water change you are going to add 15ppm K. Depending on your GH you may need to buy a bag of CaSO4 and MgSo4. If your GH is low I would add 10ppm Ca and 3ppm Mg at water change. This calculator will aid you in figuring how much of each nutrient to add. https://rotalabutterfly.com/
4. Stay on top of pruning and maintenance religously. do not skimp on this!
5. adding purigen is a good idea because there will be alot of organics in the water
The problem with aquasoil is the water column will be P limited with a very rich N source. This obviously works for amano and 1000's of other tanks, but when you add higher lighting and richer CO2 then they use it can become an issue.
If you have low lighting with heavy root feeders you could probably Just add K and micros for a long time, but the addition of P will only help things.
The ugly stages a new aquasoil tank goes through do not have to happen if you understand what is going on. There is no need to reduce lighting to avoid these issues, you just need to give the plants what they need in the water column because it's not good to run a nutrient limited tank. To clarify, by dosing just K and micro, you will have everything needed in the water column except for P, this is bad for plants and great for algae. Happy plants= Happy tank. If you supply more information about your setup, more people will be able to give you more detailed advice.