How to change ringtone when 'Ringtone' button will not select?

My phone (HTC Desire 626) likes to randomly shut off and sometimes if I'm able to get it back on (it does not like to turn on) it has reset everything, to the point where I get the instruction pop-ups for a first time user. I've been able to live with all this, I really only use the phone for phone calls, but about 2 months ago it reset itself and put the ringtones and notification sounds to default Verizon sounds. When I went to change them none of the buttons that allow for changing sounds will select. They grey when I press them, but they won’t open anything. I dealt with it even though the sounds were so low I couldn't hear them most of the time. I have updated everything and though this didn't change the sound issue it did help with the phone not randomly shutting off as often and I was able to get it to charge (that's a whole other issue), but then 2 days ago it started to be obnoxious again, randomly shutting off, not turning on, not able to charge, and now the ringtone sounds are set to silent, and I still can't change them. Now the phone is almost completely useless.

I do heavily sensor my apps' permissions on the phone. I did run into issues with that earlier this year and found that there are three apps that control basic text messages and I have to have all of them running to receive or send text messages, so is there something like that now for ringtones and notification sounds? Maybe I have it turned off because it was unnecessary with the old system version?

Welcome to Android Central! Does the phone work normally in Safe Mode? https://support.t-mobile.com/docs/DOC-28612

No it doesn't work in safe mode either. When I try to change the notification sounds for an individual contact under 'People' in the phone app it crashes and closes the app. I downloaded an app today with ringtones and was able to change it with that, but that app is very limited, in that, I cannot get sound for my alarm, only text and calling. I can still not change it under settings or even under settings for individual contacts.

What menu are you using to try to change the ringtone? Are you going to Settings>Sound​?

I've tried it from setting>sound & notification, going through all often in there, also through each apps settings, and, in the case of phone calls, from each individual contact.

Ok, when you go to Settings>Sound & Notification>Ringtone, do you get a list of all the ringtones? If you select one, does it play a sample for you? What button is greyed out there?

If buttons are greyed out, it's possible you have a screen overlay that's causing problems: https://www.howtogeek.com/271519/how...or-on-android/

When I try to select Ringtone it highlights, acknowledging my selection but does not open. I cannot access the ringtone list, it won't open. Notification sound, Alarm, and Ringtone, will not allow me to open them.

If that's happening in Safe Mode, then something is wrong with the system. You might have to do a factory reset, after backing up or syncing all of your important data first.

But first, make sure it isn't a screen overlay issue (although I don't think screen overlay would be an issue in Safe Mode).