Yeah, both updated to latest.

Both Dot 3rd gens running latest firmware?

For as long as I can remember, if I said "Alexa, set a 15 minute timer" and, some time later, said "Alexa, set a thirty minute timer" Alexa would first set a 15 minute timer, then set a second timer for 30 minutes.

For the past couple of weeks, though, this has changed. If I have that 15 minute timer running and then say "Alexa, set a thirty minute timer" it doesn't set a second timer but instead changes the first timer to 30 minutes. Now, I have to remember to specifically say "Alexa, set a second timer for 30 minutes" if I don't want to lose that first timer.

Is there any way to revert to the original setting?

I just set three different times just by saying alexa set timer five minutes, alexa set timer 10 minutes and alexa set timer 15 minutes.   

Try unplugging the echo device for at least 40 seconds.   

I have my Echo8 gen2 connected to external speakers by Bluetooth. If I receive a media feed from my wife's Echo 5 my Bluetooth disconnects and will only reconnect if I disconnect the media feed. Any ideas?

Best I can find under device settings is this little tidbit -
"Request Sounds
Play a sound when you say something to Alexa."

Keep in mind I use exclusively Apple stuff, so there may be some differences between what I am posting and the Widows System or Android phones. This should get you close enough to make a change.
 
On the phone app it is different but accessed through the device settings. On the home page on the app, choose the device icon in the upper left corner. Once you choose a device, you have to go to settings through the little gear symbol in the upper right corner. Scroll down until you see Sounds and click on that, then the option to play a sound when you make a request is in one of the bottom sections... self explanatory at that point.

If you use the web page on a computer, Go to settings on the web page - Settings > (Choose the device you want to make a sound) > Sounds. Then under "Request sounds", to turn on, choose the slider next to "start of request"

   what i want to do is this
Alexa?
"Yes"
blah blah blah

I want alexa to respond to her name as in "yes webber317" this would let me know that she heard me.
any way to set that up?

Sounds like the mute button is stuck or broken in such a way that it is always electrically on.

If it's within warranty, you should give Amazon a call and get it replaced.  According to Amazon the Echo Dot gen 3 has a 1 year warranty. https://www.amazon.com/gp/help/customer/display.html?nodeId=GDXJ4LXEEA4QNDXF#:~:text=One%2DYear%20Limited%20Warranty&text=We%20warrant%20the%20Device%20against,date%20of%20original%20retail%20purchase.

If you're unsure whether your Echo Dot is still under warranty, give them a call and they can look it up.