There are many physical wallets on the market for Bitcoin, but what if you could build your own ?
You can already do it by combining open-source software and RISC-V chips. This is possible with the M5 Stick V device. Or with the Maix Amigo. It is also possible to buy just the chip to put on your PCB.
Read more about RISC-V:
https://github.com/topics/m5stickv
https://www.hackster.io/MakerIoT2020/a-risc-v-iot-development-pcb-6ffcd8
https://www.protocol.com/enterprise/riscv-chips-architecture-open-source
https://medium.com/@nervosnetwork/risc-v-its-benefits-to-blockchain-10b505606d1f
You already can.
https://github.com/SeedSigner/seedsigner
https://github.com/cryptoadvance/specter-diy
https://github.com/Blockstream/Jade/tree/master/diy
Do these projects use RISC V?
No (although they all have software written Python, likely could work with RISC-V boards under Linux too).
My comment was answer to "what if you could build your own ?". It's possible already, without RISC-V, which is just a different CPU arch.
P.S. I plan to experiment with running Bitcoin node on RISC-V one day, so far haven't found any boards I like. Running nodes on different archs is more important than air gapped devices, where priorities should be security and cost, CPU arch is not so important.