Soyouz 1 was new technology and was bound to had some teething problems (like Apollo). Similar issues were very common even on other missions. There were backups and Soyuz 1 managed to deorbit.

Soyouz capsule is stabilized aerodynamically. And solar panel is not even on part that deorbits...

There were several delays. Problem was in parachute storage. It was kept in pod without maintenance. Before mission it must be checked and refolded, this did not happen. Parachute become moldy, sticky and did not open...

My source is a book from this guy:

Karel Pacner is a Czechoslovak journalist, with long history in soviet space mission. He was only soviet-block journalist who covered Apollo 11 on site. In 1990ties he had series book about soviet space mission based on his study of soviet archives.