Folk have ran Zram on 3B+ here before and seen advantages.
Others have run a decent swap file on HDD / SSD and seen advantages
I would not run a swap file of USB stick or SD card due to wear levelling.
Given the cost of these boxes I would say if you have lots of apps running and eating memory, look to off load some onto another Pi
Just keep an eye on memory use - if you need it move to HDD / SSD and set up a decent sized one.