Well the Apollo-Core is a modern implementation of the 68000 series, same base instruction set, but can do more instructions per cycle, with 64-bit instructions and extra multimedia functions including modern version the Amiga Paula sound chip that can do 16-bit audio and current core development is implementing a 3D accelerator core, this is all a fun hobby project from a former IBM Processor designer that loved the Amiga and 68k.. With a Cyclone V FPGA it roughly has the same CPU power around a Pentium II processor.
Even that modern reincarnation with new instructions, 64 bit, etc, continue being a CISC design. Modern x86-64 continue being CISC CPU and they have to "translate" those CISC instructions internally to execute them in an efficient way more similar to RISC (and they have to support old instructions). Decoding/"traducing"/etc of that "complex" instructions to simpler ones (similar to those on RISC) has a cost in energy, wasted transistors/space, material cost. It is one of the reasons ARM is more efficient.
And RISC-V, being obviously a RISC architecture, goes even further: for example it doesn't have flag register like was usual on most old designs I have know about. It can be shocking at first, but it is done that way because old design (having classical register flag like most architectures) for example implies a more difficult/costly parallelism and instruction reordering.
If a true SoC ASIC could be made it likely could contend with some more modern processors, but this would one be cost prohibitive and legally would be a challenge.
If it could be done in an ASIC it would be faster and much more efficient and even cheaper than a FPGA, if enough number of unites are produced. But there is the problem: probably there is no enough Amiga followers wanting to buy it so no ASIC can be produced at good cost (if you make small number, ASIC is more expensive than standard FPGA).
I remember my
C64 Direct-to-TV. It was cheap, fast, little energy consumption, etc, as it used an ASIC instead of FPGA, but the 1st production run was 250,000 units. I bough a few for 10€ each in. And it is supported/emulated in VICE Commodore 8-bit emulator.
PD: A am no Amiga fan today (I have complex reasons to do so), but I continue being Commodore 64/128 and ZX Spectrum fan today