I tried doing the challenge using a custom superflat on Java and I didn't get 0 FPS or anything but there was this weird bug where I couldn't pick up the items as the explosions were happening. Java worlds are supposed to be infinite but somehow because of a generation bug I fell literally straight off the edge and should have died but instead just fell forever down.
I think I remember once using MCToolChest to generate a world like this in Java, then port it to Bedrock, but that tool obviously converts chunks at a time so I would just have some chunks which were TNT and some which weren't. The lag I got from that was extreme but I don't remember any absurd bugs.
Unfortunately, given the processor and graphics card in your computer, you're probably going to get lag. You could try turning of the lava animations and turning all the graphics settings down to their lowest setting, but my kids have a similar computer and they get lag in vanilla minecraft (Java) with the settings turned all the way down as well.
I can get acceptable performance (around 30fps) when playing Minecraft normally.
I can take a bit of lag (needs to be good enough to be playable) as long as there's some way, even if mods are necessary, of playing this challenge again.
It seems that Minecraft X360 worked because the number of active TNTs per world was limited, so if there were too many they would just dissapear when ignited, which meant the challenge could work without titanic lag. I hope there's a mod out there which replicates this, heck, even make one myself if I need to but how'd I go about doing that?