Plate not flat

Techxy P702M - plexiglass frame - story: someone purchased it as a kit, never got it to work and passed it on/sold it to someone who knew what they were doing (something about parts installed backwards, upside down, mis-wired) - got it working - well going through the motions - sans filament. Put on Craigslist and along I came. Good price and it has a new home - some tweeking and a couple of hours later a perfect box for my ESP32-cam. I don't think a multi thousand dollar printer could have done a much better job.

I have discovered one thing - the plate seems to be concave. 1 or 2/1000 .001 or .002 (3?) A good straight edge show light at the center.. If I use a strip of paper under the extruder near the 4 corners, my prints tend not to stick to the blue tape. However when I do the paper strip in the center - extruder drags at the corners - my print sticks, and I mean sticks!

I'm thinking placing a sheet of glass over the existing plate with a ?2"? square of blue tape under the glass(support). Thoughts.
Thanks

Could the printer be a Tronxy P802M rather than the one you've noted? I searched for the printer name and the results were null.

yse, eye hhaz prob tipe'n . I'v always been hired for my good looks ...

If you can make a sheet of glass work for you, that's a good option. Aim for getting borosilicate glass, as it's more tolerant of the temperature changes. Another option would be to replace the bed with a flatter one, or fabricate your own from cast aluminum plate, which is typically machined for flatness. That option would be more challenging, as you'd have to drill holes and attach a heater, etc.

The first job would be to DEttach the heater. I haven't looked real close, but it seems to be really really attached.
Gawd ain't Amazon wonderful - took 14 seconds to find borosilicate glass for a Anet A8. And the A8 is the same as my tRONxy. I'm thinking a thin coat of heatsink compound between the aluminum & glass.

<a boy'n is toy>

PS yesterday my bag of 1000 tie wraps showed up and I spent an hour aligning wires - I'm CDO - mo-better and I can get to the sd card. Can't imagine where the mind(s) of the designer(s) were - some wireing is almost short and other wires are over a foot long. Thinking of attaching a spare RasPi.