Horizontal Lines on my display, Disappearing and Reappearing.

There are a few possible culprits here but if it were mine I’d work from least expensive to most.

Your connectors could be dirty if it’s been single-user for a few years without a service call. First thing that I would do is open the base plate, blast out debris with compressed air, and inspect the display connectors.

Clean the connector that runs from display board to motherboard (only one end will be available). I carefully use compressed air and DeOxit on a Q-tip for cleaning these connectors ports and attachments. See this guide up to step 19 to get to the port in question:

Sostituzione gruppo display del MacBook Pro 13" Touch Bar versione fine 2016

Next would be replacing that cable for the display board to motherboard. Here is the part:

[prodotto collegato mancante o disabilitato: IF123-103-2]

Unfortunately the connector is mounted to the underside of the motherboard, so to replace you will have to remove the motherboard. While the motherboard is out, I would recommend cleaning the connector with DeOxit.

The other possibility is that the flex cables on the display board have gone bad due to repeated flex. That will require replacement of the entire display assembly, in which case the display assembly guide applies as well to completion.

The display-to-motherboard connector is maybe a 70/30 chance against a positive outcome, but since it is possible and so much cheaper than total display replacement, I believe it would be worth trying.