The easy to obtain FPGAs contain ancient ARM cores, but which are usable for implementing microcontroller tasks.

For example the AMD Xilinx UltraScale+, like in the AMD Kria modules and development kits (3-digit prices), include some Cortex-R5 cores, which provide deterministic operation, like Cortex-M.

Cortex-R5 are somewhat slower than Cortex-M7 at the same clock frequency, but they are available at a higher clock frequency than many Cortex-M7 implementations.

If you can implement some custom peripherals in the FPGA logic array, then you can obtain much higher performance than with a microcontroller alone.