Hi @semmanue @Dethe1984 @a5
Can you try following steps to fix this?
1. Go to Appearance > Customize > Site Identity.
2. Remove the logo.
3. Click Publish.
4. Upload a new logo from Site Identity again.
Note that, the issue has come due to the old customizer option of the theme for the logo. So, if you follow these step should fix the issue.
If you upload the logo with the size you want, it should appear the same size. How did you try changing the size of the logo? Also, did the issue of logo not changing is fixed? Let me know about that also. Thanks.
If it’s the right size then you can press the Skip Cropping button in the next window after the upload of the Logo to keep the original size.
Then, go to Appearance > Customize > Header Options > Header Logo and select Header Logo Only or Show both header logo and text.