How to install a 1.3 workbench on harddisc on an A500?

While looking through troubleshooting stuff for SD card problems I stumbled across this page and found out something new. You can boot your Pi from USB, but it appears to be a one way deal and permanent. I remember earlier there was a way to boot from the SD and switch to USB. I may go that route if my read/write problems don't stop. See link below: https://www.raspberrypi.org/documentation/hardware/raspberrypi/bootmodes/msd.md

Amibian 1.4 doesn't work on RPi 3A+. Has anyone been able to get it working? Thanks in advance!

Hello there. Apologies if this has been asked before. I intend to purchase a Raspberry Pi purely for Amiga emulation, and was wondering if there are any benefits to getting a Pi 4 in terms of performance? Perhaps less lag or something similar? I am aware that there aren't many builds for the Pi 4 just yet. Thanks.