Wrodpress Optimization

I have a wordpress website with some issues that need to be resolved. Issues with website: 1. Gtmetrix & Google pagespeed scores need much improvement. Project will not be considered complete unless this issue is not solved. 2. Website is very sluggish in the backend. Sometimes it takes longer than 20 seconds to save/update an article. I have been told by tech support that is has to do with slow queries and optimization of database. 3. Images do not appear correctly. In some posts and categories images appear very large. 4. Excerpts are not working properly. A previous developer added “New Excerpts” in an attempt to fix issues, but it just made things worse. 5. The database is approximately 15 mgs; however, when I backup the website, the backup file is over 120 mgs… Something is very wrong. I have another website with 3 times the amount of data, and backup is only 50 mgs. Project will not be considered complete unless this issue is not solved. 6. Login menu sticks. Once clicked, the menu remains open and cannot be closed. All fixes must be done in the “Custom CSS” file. If plugins are installed, you must send me copy. All work performed must be through Teamviewer… No exceptions… Do not ask for FTP or admin user account. I have been burned too many times. The website is in Spanish (front end), so knowledge of Spanish is very useful, but not required. Please do not flood me with bids higher than the amount I am willing to pay.