I've seen much worse. Doesn't look like anything terminal.

Ditch the foil. With a 600 watter, heat isn't something you'll want to retain unless it's winter. The reflected light from the foil is negligible, and the foil restricts airflow to the roots.

I'd start thinking about transplanting into a larger pot.

A lot of folks that use MG soils use extra perlite or vermiculite to lighten the soil. This helps prevent the soil from retaining too much moisture. Consistently saturated soil is a harsh enviornment for cannabis. It prefers a wet/dry cycle. (don't overwater)

Since you're using MG soil, once you transplant...don't use nutrients for a couple or few weeks, and then only half-doses till you see their reaction. Are you giving any additional nutrients or additives?

Start thinking about what nutrients you'll want to use in the flowering stage.