The PinePhone 2 with the RK3566 will be coming at some point, which should have performance similar to a Raspberry Pi 4B. It will be based on the Quartz64 board, but I wouldn’t expect it for another 2-3 years.
If the Librem 5 v2 is released with the i.MX 8M Plus, it will have a chipset that supports up to 8GB RAM and should have roughly 20% better CPU performance, but worse GPU performance than the Librem 5 v1.
My hope is that Purism will skip the i.MX 8M Plus, and adopt the RK3588 for the Librem 5 v2, but it is unclear at this point whether it will be able to run on 100% free software. That will give us a competitive phone that is capable of running a convergent desktop, capturing 4K video and driving a 8K external monitor.