I also thank you for the nudge to look at other SMS apps.
Android version 5.0 + has a white background theme and I have just tried the "Textra" app which has a dark mode and other useful features so it's easier on my 56 year old eyes and has nice features.
You probably have the Google Hangouts app which does messaging and other things, but I have never experimented with it.
Also recommend the SMS Backup + app which saves and can restore your texts to your Gmail account on a pc if you use it with your Gmail address, and your call logs as well. Been using that 4 years.
I'm on a lunch break and needed someone to annoy so your it.
If you get to like Android there are very good value phones to recommend now at great prices if you feel like moving up to a newer model.
No more replies needed unless you have questions.
Enjoy the forums!
Say hi in the Android Central Community section - Introductions forum, or have a look.
There are also Ambassadors guides to things stuck to the "General Help and How To" section, which itself is a better questions forum for members as you get more responses from regular users.