Numerous power cables and chargers will not charge my tablet.

Hi Nick,

In most cases even if the battery is bad the device will usually run when plugged into power, a charger in this case. The fact that it isn't coming on would tend to indicate that no power is getting into the device rather than saying that the battery isn't holding power.

You've already done the first part of figuring out this problem; that of trying different chargers and cables to eliminate the power source as the problem, so I would tend to suspect the charging port may have a bad connection to the daughter card it sits on; that's the most common kind of failure with this sort of problem. If it was mine I would replace that daughter card first then reevaluate and see where you are.

Fortunately on your tablet it's actually a pretty easy job to replace that circuit board. I didn't find any written iFixit-style guides, but there's a pretty good YouTube video showing you exactly what you need to do.

Samsung Galaxy Tab A 8.0 2019 T290 T295 Charging Port Replacement - YouTube