OpenBSD starts painfully slow on one of two laptops - Why?

[nipos]

Hello guys,I'm new here and also new to OpenBSD,which I first tried about a month ago.
I installed it on two totally different laptops.
In both cases,it's the only BSD that has all important drivers and I wanted to finally get rid of Linux for various reasons.
The one laptop has a Intel Atom x7-Z8700 CPU with 4x1.6 GHz and 64GB eMMC storage,the other has a Intel Pentium Silver N5000 CPU with 4x1.1 GHz and 250GB NVME SSD storage.
With Linux and FreeBSD,both start within only a few seconds and perform well.
Now,with OpenBSD,the second laptop takes about 2-3 Minutes to boot to the graphical Login Prompt,while the other laptop takes only 10-20 seconds,which is totally okay.
Both systems were installed in the same week with nearly identical configuration.
I get that the CPU of the second laptop is a bit slower,but that doesn't explain this huge difference.
Also,it took me a few hours to install OpenBSD on that laptop because the installer took more than a minute each time to respond to most of the questions,while it responded nearly instant on the other laptop.
After the boot is finished,the "problematic" laptop also works rather good,sometimes WebKit2GTK-based browsers hang,but it can even play videos smoothly in Firefox.
Does anyone have a idea what causes that huge boot delay on one of the laptops?
I suspect it doesn't like that specific hardware,maybe some driver issue?
Is there a change to work-around it using some configuration options?
Or can I try to fix it in the source code with my very very very limited C knowledge? (But I need to know what to look for,in the first place...)