Are these sunflowers salvageable?

Hi all - I’m new to gardening, crossposting from r/gardening!

Bought 2 beautiful sunflower plants and repotted them. I tried deadheading the ones that lost petals about a week ago because it’s my understanding they don’t regrow the petals (and start to produce the seeds instead), and also because I saw some new flowers forming below. But even the new tiny ones look dead now, and some look okay but are not growing at all for 1-2 weeks. We had a few cloudy/rainy days but nothing crazy.. I’m in zone 8B of the US.

Am I able to salvage these 2 plants, or are they goners? TIA for any help!