At the moment the PC plugged into the switch has the same IPv4 as my public IP
It sounds like you are effectively "bridging" your home devices to what I call the "ISP LAN" (which is usually the "WAN" of a home router). In other words, you have the switch directly attached to both your home devices and the ISP (which "patch you through" to it with a "wall Ethernet port" or a "router-less modem"). Your home devices are therefore "exposed in the Internet" (well, assuming there's no CGNAT).
but does this mean I don’t have to change any setting to achieve port forward
More like you don't need port forwarding in this case, or more precisely, port forwarding "is not a thing" in this case. Port forwarding refers to traffics with certain destination port number would have their destination IP address "rewritten" by the original destination host and forwarded to the new destination host.
A home router can be configured to forward certain requests (that originally destined at its WAN IP, which is often a public IP) to one of its LAN host.
But when your PC is configured with a public IP address (through DHCP, I suppose), it means that traffics destined at that address can arrive at your PC without any host performing "port forwarding". (For the record, NOT referring to cases when one non-sensically statically configured a public IP on a host that is behind NAT.)
The thing is, there's a high chance you'll bump into problem with such setup, because often you can't get as many (public) IPs as you want from your ISP. You'd likely end up noticing your home devices "fighting" for one (or a few) IP, and the "losers" would lose Internet connection.
Also, home routers usually come with some kind of firewall feature (although often, not very solid), which could be desirable. (Note though you'll eventually hear false claims like "NAT by nature provides security", but stateful NAT doesn't really do that. At least communication between a WAN "neighbor" and a LAN host could be initiated and established by the former if your router or your ISP does not properly forbid it.) And having your own broadcast domain might be something that is desirable too.