TouchID and 3D touch issues after battery replacement

Hello everybody, I’m new here in the forum so I hope I’m asking my question properly. I just got my iPhone 7’s battery replaced and now I have two new unwanted features I’m asking you advice for:

# TouchID playing weirdly: I’ve search and read some other questions about TouchID not working, but my problem seems a little different. My home button works perfectly, the double tap to lower the status bar works, but when I’m asked to scan my fingerprint and I put my finger on the home button as usual, the screen starts moving it’s status bar rapidly up and down as if I were rapidly double touching the home button like ten times per second. As a result, it scans nothing. I managed to disable it from the settings, but there are still some apps that I can’t access because I can only disable the setting from inside the app and not from the phone’s setting;

# My beloved 3D touch is totally missing, and I really miss it. I’ve read this could be matter of the screen sealing to the phone’s body, am I right?

So while the 2nd feature is more a matter of habit I hope I’ll overcome soon, the more time passes the more I realize I need my TouchID back because some apps are still hostage of my fingerprint, and I’m referring to payment apps and bank accounts that totally relies on iPhones’ authentication security.

From what I just told you, do you think it’s something easily fixable on my own and worth buying a new screen seal on Amazon (sold at like 8€, I’d better buy a new battery kit lol)? Or it’s too risky or there’s something different I should replace? My home button works as usual except this psychedelic new feature so I’d be disappointed if I should replace my whole button.

I also thought I could make my screen changed because sometimes when it overheats some images remains impressed on the screen, but I'm procrastinating it because it's not a so annoying problem since it happens rarely. Instead, if I do try to change the screen, would it be of any help in fixing the TouchID? What do you think?

Really thank you to everybody will try to answer my question.