Would it be possible to share your store URL so that I and fellow community members can take a closer look at this?
The most common reason for logo size issues when uploading pictures to your store is the additional background. Even if this is a transparent background, the sizing can be off.
It also may be something to do with the theme directly, you may be able to edit the size within Online Store > Themes > Customize. Sometimes, however, you may need to reach out to your theme developers if this is something you need assistance with. As this is a third party theme, you will need to reach out to your theme developer to get them to make these changes for you as this would not be supported by Shopify. As you mentioned you are using Debutify, I have found their contact information for you.
Hopefully, once you share your store URL, someone with more technical skills in the community will come across this and be able to add some value to you here, but if not, your best bet might be to reach out to one of our Shopify Experts, who you can hire to do almost any custom work on your store.
If you were to reach out to them about this query, they would be able to resolve this issue for you.
Thank you for sharing your store URL and for the additional context.
However, it looks like the store is password-protected, so I am unable to see the logo itself.
Have you tried to upload the logo once more with minium focus on the background in Settings > Files, just to see if this assists you? Bearing in mind that even though the image is on a transparent background, it is still considered part of the file size once you upload this.
But great work on reaching out to Debutify as it may be something within the theme that is making the image smaller, and some changing to the code, may assist with this.
As it would require a coding change, this would be done via the likes of your theme developer or as I mentioned by hiring an expert, as they would be more than capable of changing the code if needed.