Unable to boot -CURRENT on Thinkpad P16s G2

Hi everyone,

we have a Lenovo Thinkpad P16s Gen2 (Type 21K9) here with an AMD Ryzen 7 
CPU which we would like to install FreeBSD on. Alas, it won't boot.

The FreeBSD 15-CURRENT amd64 snapshot from February 22 hangs after:
[...]
acpi_acad0: <AC Adapter> on acpi0
battery0: <ACPI Control Method Battery> on acpi0

A verbose boot provides some more information, but then hangs as well:
[...]
acpi_acad0: <AC Adapter> on acpi0
AcpiOsExecute: task queue not started
battery0: <ACPI Control Method Battery> on acpi0
AcpiOsExecute: task queue not started
ACPI: Enabled 1 GPEs in block 00 to 1F
ahc_isa_identify 0: ioport 0xc00 alloc failed
ahc_isa_identify 1: ioport 0x1c00 alloc failed
ahc_isa_identify 2: ioport 0x2c00 alloc failed
ahc_isa_identify 3: ioport 0x3c00 alloc failed
ahc_isa_identify 4: ioport 0x4c00 alloc failed
ahc_isa_identify 5: ioport 0x5c00 alloc failed
ahc_isa_identify 6: ioport 0x6c00 alloc failed
isa_probe_children: disabling PnP devices
atkbdc: atkbdc0 already exists; skipping it
atrtc: atrtc0 already exists; skipping it
attimer: attimer0 already exists; skipping it
sc: sc0 already exists; skipping it
isa_probe_children: probing non-PnP devices
sc0 failed to probe on isa0
vga0 failed to probe on isa0
fdc0 failed to probe at port 0x3f0-0x3f5,0x3f7 irq 6 drq 2 on isa0
ppc0: cannot reserve I/O port range
ppc0 failed to probe at irq 7 on isa0
uart0 failed to probe at port 0x3f8 irq 4 on isa0

Booting with ACPI disabled results in a kernel panic.

An older snapshot (-CURRENT from 15. February) as well as 
14-STABLE/-RELEASE fail to boot in the same manner.

Does anyone have any suggestions on how to proceed at this point? We 
really would like to get FreeBSD running on this machine and are willing 
to help. As neither of us is versed in low-level system programming, we 
would require some support.

Currently, the notebook is running Lubuntu 22.04 from which we gathered 
some information about the hardware. Everything we collected so far can 
be found here: https://philippost.de/TP-P16s-G2/ If there is anything 
missing, please indicate which information you require.

Thanks a lot in advance!

Best
Philipp and Klaus