I got the PUAE Amiga core to work on Switch. I added it to the Switch buildbot yesterday! It should already be in the latest nightly.
BIOS files:
"kick34005.A500" Kickstart v1.3 (Rev. 34.005) Amiga 500 md5: 82a21c1890cae844b3df741f2762d48d
"kick40063.A600" Kickstart v3.1 (Rev. 40.063) Amiga 600 md5: e40a5dfb3d017ba8779faba30cbd1c8e
"kick40068.A1200" Kickstart v3.1 (Rev. 40.068) Amiga 1200 md5: 646773759326fbac3b2311fd8c8793ee
Put BIOS files in Retroarch system folder e.g. "/retroarch/cores/system/"
It is very rough, but it already allows playing IK+ with sound fx, something that I couldn't get to work in UAE4All2! Just turn off Compatible Mode in quickmenu->options to make the sound fx in IK+ work. The option requires a restart of the core to take effect.
Currently, there are quite some problems, for example there's a confusing GUI that only shows correctly when hi-res mode is enabled, and there's no two-player support yet.
Sonninnos and I will be working on improving this core.