Hi.
I'm Evgenia, senior web and mobile UI/UX designer who has 3 years of experience in the design field.
In 3 years of my design career, I have been designing so many new websites and mobile apps or redesigning.
So I have acquired rich experience in each different style of design.
I have read your job description, so I think Adobe Xd will be comfortable better than Photoshop for Mobile app UI design.
But if you want it I will provide you as original Photoshop files.
A few weeks ago, I have done a design of the chat app, maybe it'll be a similar app that you want.
You can see my recent work in my portfolio.
From my experience, Contrast, font, color, kerning, proximity, and white space, etc are the primary keys in the design and the most important things are color and font, background.
The most important thing is color and font, background, etc on website design.
As you can see in my portfolio, I like doing design as a material design style.
So I know well what I have to do it. Also, it is a good fit for my hobby and as your requirement.
If you think my skill and experience fit your project contact me anytime.
I am looking forward to your reply.
Regard
Evgenia Isaeva.