does the element come with the thermostat in it?

Here are your parts
Model REX6634PQ0

Here is the wiring diagram
https://www.servicematters.com/d...0Sheet%20-%208528187.pdf

First I would check the breaker/fuses. Turn the breaker off/on slowly a couple times. Often you can loose half the line voltage without actually tripping the breaker. Depending which side drops out the units motor will run but you get no heat or timer advance in either timed or auto modes. Both the heater and the timer require 240 volts. If the timer advances on timed dry then your 240 is probably OK and the heater is probably open.

On Auto modes the timer gets power through the heater coil when it is turned Off by the thermostat.

Thought I had given you a recommendation.

So here is another one

I would suggest you purchase a meter. You can get a decent digital multimeter for under $20.00. You do not need fancy though it is nice if the leads are a couple feet long.
If it saves ordering one unnecessary part it has paid for itself and you end up owning a useful tool.

Use the meter to check that you have 240 volts.
If you have the 240 then use the meter to check the heating components.
Unplug the unit.

A couple things to watch when measuring ohms and continuity
1. Always remove power from the machine otherwise you could blow your meter.
2. Always disconnect at least one side of any device you are checking. This eliminates the possibility of measuring an alternate/parallel circuit path.
3. When checking for closed contacts and continuity use the lowest scale (Usually 200 ohms). Then try higher scales. This scale is 0 to 200 ohms so if the device you are measuring is 300 ohms this scale would show an open circuit which it is not, you are just measuring outside the scale's dynamic range.

There is a good STICKY at the start of this forum about it's use.

should i just buy a new dryer?
Cannot answer this, it is up to you. The dryer is relatively new, if you feel uncomfortable messing with it, you may want to place a service call but it should not be a difficult fix and you will save yourself at least $50.00 to $100.00.

what would you guys suggest the most common things to go out on these?
Most common would be the thermal fuse in the heater circuit (look at the wiring diagram)

Here again is the link to your parts, just so it is handy.
Model REX6634PQ0

Take a look at in the "Bulkhead Parts" section Item 6. You will see that it is a fuse and a high temp thermostat. They come as a set. The fuse can be checked without a meter.

Unplug the machine
Remove the two wires from the thermal fuse and short them together
Tape them up so they cannot short to anything.
Plug the unit back in and give it a try.
If it now runs order the parts.

Replace the fuse and high limit thermostat ASAP as they are safety devices.
Make sure you have the unit unplugged when working on it. It is 240 volts which is very dangerous.

If it is the fuse that is blown, clean and check your vent system. A dirty/clogged vent or vent louvers which do not open properly are a common cause of this fuse blowing. Also make sure your lint filter is clean.
If you use liquid fabric softener it can coat the screen drastically reducing air flow. If this is the case clean it with soap and water. Let it dry good before reinstalling.

tried that and that did not work any other suggestions?