Laptop running too hot, 23.04, almost fresh install

I have a recurring problem with my Dell XPS 9700 and Ubuntu 23.04: the CPU temperature rises to about 60°C causing the fans to get annoyingly loud. There is no apparent load on the CPU that could be causing this - at least as far as I can see. Below is the output of sensors to show the problem.

This problem occurred with a previous install, which is why I did a fresh install of Ubuntu 23.04. Luckily for me, this solved the problem for about two weeks. And now I'm back at square one.

What I tried in the previous install is to use tools like i8kmon to "fine-tune" the fan speeds, but this only resulted in a oscillating system (temperature-wise and noise-wise). I know that this laptop is capable of quite low temperatures under idle conditions. So there must be something going on...

What can I do to diagnose this issue? Is there any information I should provide?

ucsi_source_psy_USBC000:002-isa-0000
Adapter: ISA adapter
in0:          18.00 V  (min = +26.35 V, max = +20.00 V)
curr1:         6.50 A  (max =  +6.50 A)

iwlwifi_1-virtual-0
Adapter: Virtual device
temp1:        +40.0°C  

ucsi_source_psy_USBC000:004-isa-0000
Adapter: ISA adapter
in0:           5.00 V  (min =  +5.00 V, max =  +5.00 V)
curr1:         0.00 A  (max =  +1.50 A)

dell_smm-isa-0000
Adapter: ISA adapter
fan1:        2633 RPM  (min =    0 RPM, max = 3300 RPM)
fan2:        2626 RPM  (min =    0 RPM, max = 3300 RPM)
temp1:        +64.0°C  
temp2:        +58.0°C  
temp3:        +54.0°C  
temp4:        +63.0°C  
temp5:        +61.0°C  
temp6:        +40.0°C  
temp7:        +60.0°C  
temp8:        +36.0°C  

nvme-pci-0200
Adapter: PCI adapter
Composite:    +36.9°C  (low  =  -5.2°C, high = +82.8°C)
                       (crit = +87.8°C)

ucsi_source_psy_USBC000:003-isa-0000
Adapter: ISA adapter
in0:           0.00 V  (min =  +0.00 V, max =  +0.00 V)
curr1:         3.00 A  (max =  +0.00 A)

ucsi_source_psy_USBC000:001-isa-0000
Adapter: ISA adapter
in0:           5.00 V  (min =  +5.00 V, max =  +5.00 V)
curr1:         0.00 A  (max =  +0.00 A)

coretemp-isa-0000
Adapter: ISA adapter
Package id 0:  +64.0°C  (high = +100.0°C, crit = +100.0°C)
Core 0:        +61.0°C  (high = +100.0°C, crit = +100.0°C)
Core 1:        +63.0°C  (high = +100.0°C, crit = +100.0°C)
Core 2:        +62.0°C  (high = +100.0°C, crit = +100.0°C)
Core 3:        +63.0°C  (high = +100.0°C, crit = +100.0°C)
Core 4:        +62.0°C  (high = +100.0°C, crit = +100.0°C)
Core 5:        +62.0°C  (high = +100.0°C, crit = +100.0°C)
Core 6:        +62.0°C  (high = +100.0°C, crit = +100.0°C)
Core 7:        +63.0°C  (high = +100.0°C, crit = +100.0°C)

pch_cometlake-virtual-0
Adapter: Virtual device
temp1:        +74.0°C  

BAT0-acpi-0
Adapter: ACPI interface
in0:          12.46 V  
curr1:       1000.00 uA