Spotify for ios 12

[user-removed]

Hello
I'm a recent spotify premium user
I wanted to ask you two things how can I restore all hidden songs? many do not remember the title
if i delete and put the app back do i find them by default?
second thing
during playback I active I would only normalize audio
what makes the volume identical for all tracks?
can you suggest me some other setting to improve listening

Info:

ios 12

iphone 5s

spotify Premium
thank you
regards
OP

[user-removed]

Hello
Unfortunately
the problem persists
can you help me
thank you