I ordered a replacement screen from the M5Stack store on Aliexpress.
New TFT display + bezel arrived 15 days later.

Installation was reasonably straight forward.

You'll need:

• Soldering iron - I'm using old faithful Jaycar Duratech TS-1554 20W/130W
• Solder - I'm using cheap 0.5mm Sn 63 / Pb 37 / Flux 1.2
• Flux - I use a pen
• T6 Torx screwdriver - I have one of these sets

Steps:

• Remove bottom battery/breakout board
• 2x T6 Torx screws hold the PCB in place
• Slide speaker out (careful of it's thin wires - I broke mine)
• Slide PCB sideways and lift slightly. The display ribbon cable prevents it from being fully removed
• Push the display + bezel from behind to detach it from the case
• Remove the bezel from the broken TFT
• Rotate the PCB 45 degrees and remove from plastic shell, to avoid damaging it
• Flip TFT 90 degrees revealing its flexible cable
• Detach the TFT by applying a little flux + solder and gently prying while heating the pins with a soldering iron
• Apply flux to the solder pads and stroke each with a soldering iron to create a smooth finish. There should already be enough solder remaining, if not, add a tiny bit more and stroke smooth
• Place the new TFT over the pins and precisely hold in place with your thumb while applying power to check the display works
• Solder pin 1, check alignment and adjust if need be
• Solder the remaining pins. Get some bright light and a magnifying glass and make sure none of the pins are bridged. Or use continuity mode on your multimeter to check adjacent pins
• Insert the PCB + new TFT back into the plastic case, slide PCB sideways and attach Torx screws.
• I accidentally detached one of the speaker wires earlier, so with the new TFT flipped out of the way, resoldered the speaker wire.
• In doing so, I detached the other speaker wire! So I swapped both for new thinker wire, salvaged from a Dupont ribbon cable. The wire can't be too think as it needs to sit between the TFT and PCB.
• Reseat the speaker
• Sit the TFT in place and remove the protective cover (green tab) being careful not to touch it with your oily fingers
• Remove the sticker from the back of the bezel and insert the 3 plastic buttons
• Attach the bezel onto the plastic case and press firmly
• Plug in USB and boot
• Press 3 push buttons to cycle through RGB colours
• It works!

I ordered a replacement screen from the M5Stack store on Aliexpress.
New TFT display + bezel arrived 15 days later.

Installation was reasonably straight forward.

You'll need:

• Soldering iron - I'm using old faithful Jaycar Duratech TS-1554 20W/130W
• Solder - I'm using cheap 0.5mm Sn 63 / Pb 37 / Flux 1.2
• Flux - I use a pen
• T6 Torx screwdriver - I have one of these sets

Steps:

• Remove bottom battery/breakout board
• 2x T6 Torx screws hold the PCB in place
• Slide speaker out (careful of it's thin wires - I broke mine)
• Slide PCB sideways and lift slightly. The display ribbon cable prevents it from being fully removed
• Push the display + bezel from behind to detach it from the case
• Remove the bezel from the broken TFT
• Rotate the PCB 45 degrees and remove from plastic shell, to avoid damaging it
• Flip TFT 90 degrees revealing its flexible cable
• Detach the TFT by applying a little flux + solder and gently prying while heating the pins with a soldering iron
• Apply flux to the solder pads and stroke each with a soldering iron to create a smooth finish. There should already be enough solder remaining, if not, add a tiny bit more and stroke smooth
• Place the new TFT over the pins and precisely hold in place with your thumb while applying power to check the display works
• Solder pin 1, check alignment and adjust if need be
• Solder the remaining pins. Get some bright light and a magnifying glass and make sure none of the pins are bridged. Or use continuity mode on your multimeter to check adjacent pins
• Insert the PCB + new TFT back into the plastic case, slide PCB sideways and attach Torx screws.
• I accidentally detached one of the speaker wires earlier, so with the new TFT flipped out of the way, resoldered the speaker wire.
• In doing so, I detached the other speaker wire! So I swapped both for new thinker wire, salvaged from a Dupont ribbon cable. The wire can't be too think as it needs to sit between the TFT and PCB.
• Reseat the speaker
• Sit the TFT in place and remove the protective cover (green tab) being careful not to touch it with your oily fingers
• Remove the sticker from the back of the bezel and insert the 3 plastic buttons
• Attach the bezel onto the plastic case and press firmly
• Plug in USB and boot
• Press 3 push buttons to cycle through RGB colours
• It works!

If you're thinking combined shipping, I'm located in Sydney (CBD) in Australia.

M5Stack Store replied on AliExpress.

The screen is a custom design and to buy a replacement I need to order 13x the $1 USD custom made order:
https://www.aliexpress.com/store/product/M5Stack-Special-Link-for-Custom-Made-Order/3226069_32844904816.html

Which works out roughly $17 AUD and is about 30% of the price of a new unit.
Might just use this one for spare parts and order a new one.

Product page says its a 2.0" TFT-LCD 320x240.

Back of the screen says "FW-TFT020 YSH 2017-09-25"

I bought a new grey m5stack (MPU9250) and it arrived with a cracked screen!

Rather than return the unit and wait another month or two for shipping, would it be possible to replace the TFT?

Is it a 2.2" ILI9341?

There's heaps of them on aliexpress, but I'm not sure which specific screens would be compatible.
There's 2.8", 2.6", 2.4" and 2.2". Green tab, red tab, black tab etc.

Does anyone know the specifics on which TFTs they use and/or provide a link to buy a replacement?

The plastic screen cover is fine. It's just the TFT.