There’s already iSH[1] that emulates an x86 Alpine Shell and UTM[2] which provides x86 emulation with a full GUI.
You can either join their Test Flight to install (until Apple takes it down), build and install yourself (good for 90 days and then you have to rebuild), or Jailbreak and install with no hassle.
So, jailbreaking is definitely not necessary, but would be easier due to Apples code signing policies.
UTM is not available via TestFlight because it requires entitlements that cannot be used for apps submitted to Apple. UTM also does a lot more than just x86.
You can either join their Test Flight to install (until Apple takes it down), build and install yourself (good for 90 days and then you have to rebuild), or Jailbreak and install with no hassle.
So, jailbreaking is definitely not necessary, but would be easier due to Apples code signing policies.
[1] https://ish.app/ [2] https://getutm.app/