Plywood Backed Drywall Equivalent to Studs for Hanging a TV?
If this were 1/2&quot; plywood, I would have no concerns at all. With 1/4&quot;, it is a bit iffy. The plywood itself is relatively strong, particularly sandwiched between drywall and studs. The concern I have is whether the screws in the plywood have enough depth to grip well.
What would definitely work, if there is enough space behind the drywall/plywood, is toggle bolts:

This is a randomly selected assortment on Amazon, but you can get them from any hardware store. With drywall there is always a little concern you might hit a weak spot that was previously patched up. With plywood backing, toggle bolts can hold plenty of weight.