I hope you are well today and thank you for your questions.
I’d like to modify my post-title background color to be as the one here; just when I hover over the area of the post, only.
We can achieve this developing custom CSS code.
Could you please share me your site URL where the post titles are displaying so that i can help you to achieve it?
Also, I want to add an effect on the images while loading in order to be blurred; as it appears in this example.
To achieve this you have to develop more custom code.
Developing custom code for custom functionality is beyond the scope of support that we provide here. Please see https://themeforest.net/item/jevelin-multipurpose-premium-responsive-wordpress-theme/14728833/support
If you are not a developer then you can consider hiring a developer to develop it for you. You can hire a developer from any freelance site. Shufflehound recommends the developer https://www.upwork.com/freelancers/~011652ffec8865c6d5