No or Very Low Heat on Older Frigidaire

After looking for any posts which could help me, I found nothing. The tech sheet I found reference ‘better’ models have a digital display and the ‘good’ models do not. Our builder said he had a great deal for us with our appliances… come to find out not such a great deal. Needless to say I have worked on every appliance and repaired each of the Frigidaire appliances in our house, except for this dryer!

Sometime last week I noticed the heat was weak, so I cleaned out the lint trap, vent, and vent duct from the dryer to the outside of our home. Was a bit congested yet not blocked. At this point I have very little heat if at all. I can turn the dial to any setting and the temp does not seem to rise. Maybe 85-100 degrees, and this takes 5-10+ cycles to dry a light load. Not really working well for the wife…

Please guide me, as in the past this forum has helped tremendously! I will troubleshoot to the best of my ability. I need an idea what I should do…

The only digital display is the estimated time remaining…

Thank you kindly for all of your time and help.
Scott