Difference in processor performance in base 13" Mid 2020 and upgraded 13" Mid 2020 MacBook Pro?

Sure, you can trust geekbnech for quite neutral results for CPU capabilities for macs in the last 5 years.

That being said, I’m never in a case where the CPU is what is actually holding me back. The things that chew CPU are never things I’m waiting on and I go have dinner or let it run to complete. The things that make me happy are good software, efficient software, not having memory leaks and fast storage.

I get that on a 2015 MacBook with a 1.2 GHz CPU and NVMe SSD with 8 GB of RAM. All of the machines you specify are overkill for what I need. The question is what benchmark and code do you run - can you profile it on your current mac and then decide if the investment in a new mac is worth the money in time you save.

No benchmark will tell you that.