Lawn care after winter - How do I proceed?

Hello everyone :)

Since I came across many contradictory pieces of information during my research on the internet, I wanted to get some feedback/ideas from you on how lawn care after winter should best be done.

Attached you will find two pictures of the current condition of my lawn (brown spots like in the pictures are present all over the lawn).
The lawn was treated again in autumn with a "fall fertilizer".
The lawn was seeded in summer 2019.

How would you proceed here to make the lawn "fit" again?

Scarify? If yes, when is the best time for this?
Fertilize, if yes, which and when?

What else can you recommend?

Thanks & regards
Jörg

Loosen the brown spots a bit and keep the feet still for the next 3-4 weeks. At the end of March, under suitable conditions, then mow and fertilize.

We will now scarify as soon as it no longer freezes at night. Then put fertilizer on and water a lot. The brown spots in your lawn look as if the fertilizer has stayed on them.

rake the brown spots a bit and keep your feet still for the next 3-4 weeks. At the end of March, under suitable conditions, then mow and fertilize.

Just rake the brown, matted spots? So not scarifying?

We will now verticut as soon as it no longer freezes at night. Then fertilizer on and plenty of watering. The brown spots in your lawn look like the fertilizer stayed on there.

I think less fertilizer, as the spots only appeared after the snow has melted.

Scarifier cuts into the turf, I would only aerate, that is remove the dry dead grass. Fertilize only when the temperature is above 5 degrees at night daily, and overseed 2 weeks later.