Graphics card alone will set you back ~$500 for a 3080 (10gb) or $1K+ for a 3090 (24gb), laptops are the most expensive cost to performance option so unless you spend a lot of time traveling and getting bored I would just build a rig.
Honestly though, for what you're doing, you might wanna just get a new case with better airflow, your hardware should be more than sufficient if you're running Med/High VFX Quality, 100 Resolution Scaling, & Dynamic Resolution OFF.
Are you running it from an SSD and what form factor is your motherboard (ATX, mATX, or ITX)? The RX 580s generate a lot of heat, are you monitoring the temperature? Adrenalin has a "Performance Overlay" that'll display GPU temp, also, I would make sure AMD Anti-Lag is turned on, reset the shader cache, go to Gaming -> Graphics -> Advanced and Reset Shader Cache, and if you're running other apps like Discord, Chrome, etc. then disable "Hardware Acceleration" on those as it'll compete with D2R for GPU util. You can also check in Windows that your power plan is set to "High Performance" and make sure "Game Mode" is ON.