I could not find any tech info on this unit so have to do some guessig.

Also it looks like the timer/control board is no longer available.
[COLOR="Blue"]
Relays all seem to be working, no error codes.[/COLOR]
Most ovens do not give an error when there is a bad relay.
But the relay is not working correctly if wedging it closed does get the unit hotter.

Does the unit come ready or does it stay in pre-heat?

If it comes ready then the problem may be in the oven sensor circuit.
Check where the sensor connects to the board and the tracks to the first component down the line for cracks etc.

If the unit stays in pre-heat then for some reason the relay is not closing. Check the tracks etc. to the relay coil.
Could be the relay coil is open.
Also could be that the electronics controlling the relay are shot.

Cold solder joint checks.
A cold solder joint is often a duller gray and may also have pin holes.
Sometimes if you gently wiggle the component you will see the component's leg move in the solder joint.
You may be able to see cracks across the copper trails on the back side of the board.
A magnifying glass come in handy when doing the above checks.

There are companies out there that repair obsolete timers just Google "appliance timer repair"