TPM is still part of what they’re calling “minimum system requirements” but they’re allowing you to install without it. There will be big scary warnings though and they’re threatening to not provide support.
Time will tell what happens. I believe if they see a significant portion of Windows 10 users on legacy devices without TPM upgrade to 11 they’ll continue to support it because the data they suck up is more valuable to them than the effort to support it.
The OS being unsupported is a terrible idea. Especially is you’re relying on Defender for EDR… either switch OS’es or upgrade. There is no sense in running vulnerable devices. You’re only creating more attack surfaces. I sympathize with the user that can’t afford an upgrade, but they gotta aware and accountable of the consequence. Arch, btw