The Air will slow down if asked to do multithreaded tasks for long periods of time - it has no fan, so it can't sustain peak performance forever. And Geekbench only measures peak since the tests run for short periods of time. If you were doing something that exercised all cores for long periods of time, the 2019 would likely be faster.
If this is something which concerns you, you'd want to upgrade to the 13" MacBook Pro at minimum. It has a fan and will maintain the performance as measured in Geekbench indefinitely.
I did see comparison tests a long time ago where, in some workloads, the late 2019 i9 could beat a M1. But in general, yes that performance is real. The M1 is very good relative to what Intel was making in 2019.
On RAM - If you actually need 32GB, you still need 32GB. Lots of people get confused ideas about how RAM relates to performance. The real way to look at it is that once you have enough RAM, your software will run as fast as it can given the CPU and GPU you've got, and if you don't have enough RAM, performance will suffer. There's usually not a lot of benefit to more RAM than that minimum amount.
Basically, if your workload causes tons of swapping at 16GB RAM, and little or none at 32GB, you want 32 for sure. If you think that's the case, look at a 14" or 16" with M1 Pro. (and as an additional benefit, these machines will offer a substantial performance upgrade over the M1 13" and Air, especially for any software which uses the GPU.)