1- what do u think about the pictures of last week? (how we can fix our little problems?)
The newer top mutated growth looks to me like overwatering. You'll also want to monitor the EC of the solution your feeding with. Looks to have some nitrogen toxicity and some potassium deficiency this could all be from a lockout in the medium. knowing your EC will help with this.
growdiaries.com/journal/what-is-electric-conductivity-ec-and-total-dissolved-solids-tds
2- we ask suggestions for the distance of the lamp LED MarsHydro TS3000 (last weeks)
Look at the manufactures web page. 12" at different dim settings seems to be the go to, could always try 100% at 15-18" if you plants are showing signs of stress. https://www.mars-hydro.com/ts-3000-led-grow-light
3- we should do an other defoliation?
no use some LST
growdiaries.com/journal/is-it-safe-to-defoliate-cannabis
growdiaries.com/journal/how-to-do-low-stress-training-lst-on-cannabis-plants
4- what about flush? 🙏�👽
not unless its needed. Your plants are not near their end of life yet. Still look like they have some time to go. No brown pistils.
only other reason to flush is an incorrect ratio or concentration of nutrients was provided and you need to wash it away before it causes bigger issues.
Good Luck!